Thammasat University Hospital

Influenza A (H5N1) is endemic in poultry across much of Southeast Asia, but limited information exists on the distinctive features of the few human cases. In Thailand, we instituted nationwide surveillance and tested respiratory specimens by polymerase chain reaction and viral isolation. From January 1 to March 31, 2004, we reviewed 610 reports and identified 12 confirmed and 21 suspected cases. All 12 confirmed case-patients resided in villages that experienced abnormal chicken deaths, 9 lived in households whose backyard chickens died, and 8 reported direct contact with dead chickens. Seven were children <14 years of age. Fever preceded dyspnea by a median of 5 days, and lymphopenia significantly predicted acute respiratory distress syndrome development and death. Among hundreds of thousands of potential human cases of influenza A (H5N1) in Asia, a history of direct contact with sick poultry, young age, pneumonia and lymphopenia, and progression to acute respiratory distress syndrome should prompt specific laboratory testing for H5 influenza.

BACKGROUND AND AIM: Gastric cancer is a major health burden in the Asia-Pacific region but consensus on prevention strategies has been lacking. We aimed to critically evaluate strategies for preventing gastric cancer. METHODS: A multidisciplinary group developed consensus statements using a Delphi approach. Relevant data were presented, and the quality of evidence, strength of recommendation, and level of consensus were graded. RESULTS: Helicobacter pylori infection is a necessary but not sufficient causal factor for non-cardia gastric adenocarcinoma. A high intake of salt is strongly associated with gastric cancer. Fresh fruits and vegetables are protective but the use of vitamins and other dietary supplements does not prevent gastric cancer. Host-bacterial interaction in H. pylori infection results in different patterns of gastritis and differences in gastric acid secretion which determine disease outcome. A positive family history of gastric cancer is an important risk factor. Low serum pepsinogens reflect gastric atrophy and may be useful as a marker to identify populations at high risk for gastric cancer. H. pylori screening and treatment is a recommended gastric cancer risk reduction strategy in high-risk populations. H. pylori screening and treatment is most effective before atrophic gastritis has developed. It does not exclude the existing practice of gastric cancer surveillance in high-risk populations. In populations at low risk for gastric cancer, H. pylori screening is not recommended. First-line treatment of H. pylori infection should be in accordance with national treatment guidelines. CONCLUSION: A strategy of H. pylori screening and eradication in high-risk populations will probably reduce gastric cancer incidence, and based on current evidence is recommended by consensus.

Carbapenem-resistant Gram-negative bacteria, in particular the Acinetobacter baumannii-calcoaceticus complex and Enterobacteriaceae, are escalating global public health threats. We review the epidemiology and prevalence of these carbapenem-resistant Gram-negative bacteria among countries in South and Southeast Asia, where the rates of resistance are some of the highest in the world. These countries house more than a third of the world's population, and several are also major medical tourism destinations. There are significant data gaps, and the almost universal lack of comprehensive surveillance programs that include molecular epidemiologic testing has made it difficult to understand the origins and extent of the problem in depth. A complex combination of factors such as inappropriate prescription of antibiotics, overstretched health systems, and international travel (including the phenomenon of medical tourism) probably led to the rapid rise and spread of these bacteria in hospitals in South and Southeast Asia. In India, Pakistan, and Vietnam, carbapenem-resistant Enterobacteriaceae have also been found in the environment and community, likely as a consequence of poor environmental hygiene and sanitation. Considerable political will and effort, including from countries outside these regions, are vital in order to reduce the prevalence of such bacteria in South and Southeast Asia and prevent their global spread.

Despite advances in diagnosis, surgery, and antimicrobial therapy, mortality rates associated with complicated intra-abdominal infections remain exceedingly high.The 2013 update of the World Society of Emergency Surgery (WSES) guidelines for the management of intra-abdominal infections contains evidence-based recommendations for management of patients with intra-abdominal infections.

The CIAOW study (Complicated intra-abdominal infections worldwide observational study) is a multicenter observational study underwent in 68 medical institutions worldwide during a six-month study period (October 2012-March 2013). The study included patients older than 18 years undergoing surgery or interventional drainage to address complicated intra-abdominal infections (IAIs). 1898 patients with a mean age of 51.6 years (range 18-99) were enrolled in the study. 777 patients (41%) were women and 1,121 (59%) were men. Among these patients, 1,645 (86.7%) were affected by community-acquired IAIs while the remaining 253 (13.3%) suffered from healthcare-associated infections. Intraperitoneal specimens were collected from 1,190 (62.7%) of the enrolled patients. 827 patients (43.6%) were affected by generalized peritonitis while 1071 (56.4%) suffered from localized peritonitis or abscesses. The overall mortality rate was 10.5% (199/1898). According to stepwise multivariate analysis (PR = 0.005 and PE = 0.001), several criteria were found to be independent variables predictive of mortality, including patient age (OR = 1.1; 95%CI = 1.0-1.1; p < 0.0001), the presence of small bowel perforation (OR = 2.8; 95%CI = 1.5-5.3; p < 0.0001), a delayed initial intervention (a delay exceeding 24 hours) (OR = 1.8; 95%CI = 1.5-3.7; p < 0.0001), ICU admission (OR = 5.9; 95%CI = 3.6-9.5; p < 0.0001) and patient immunosuppression (OR = 3.8; 95%CI = 2.1-6.7; p < 0.0001).

This randomised, double-blinded, placebo-controlled study was primarily aimed to evaluate the potential of risperidone to prevent postoperative delirium following cardiac surgery with cardiopulmonary bypass and the secondary objective was to explore clinical factors associated with postoperative delirium. One-hundred-and-twenty-six adult patients undergoing elective cardiac surgery with cardiopulmonary bypass were randomly assigned to receive either 1 mg of risperidone or placebo sublingually when they regained consciousness. Delirium and other outcomes were assessed. The confusion assessment method for intensive care unit was used to assess postoperative delirium. The incidence of postoperative delirium in the risperidone group was lower than the placebo group (11.1% vs. 31.7% respectively, P=0.009, relative risk = 0.35, 95% confidence interval [CI] = 0.16-0.77). Other postoperative outcomes were not statistically different between the groups. In exploring the factors associated with delirium, univariate analysis showed many factors were associated with postoperative delirium. However multiple logistic regression analysis showed a lapse of 70 minutes from the time of opening eyes to following commands and postoperative respiratory failure were independent risk factors (P=0.003, odds ratio [OR] = 4.57, 95% CI = 1.66-12.59 and P=0.038, OR = 13.78, 95% CI = 1.15-165.18 respectively). A single dose of risperidone administered soon after cardiac surgery with cardiopulmonary bypass reduces the incidence of postoperative delirium. Multiple factors tended to be associated with postoperative delirium, but only the time from opening eyes to following commands and postoperative respiratory failure were independent risk factors in this study.

Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae have rapidly spread worldwide and pose a serious threat for health care-associated (HA) infection. We conducted molecular detection and characterization of ESBL-related bla genes, including bla(TEM), bla(SHV), bla(CTX-M), bla(VEB), bla(OXA), bla(PER), and bla(GES), among 362 isolates of ESBL-producing E. coli (n = 235) and ESBL-producing K. pneumoniae (n = 127) collected from patients who met the definition of HA infection at two major university hospitals in Thailand from December 2004 to May 2005. The prevalence of ESBL-producing E. coli and ESBL-producing K. pneumoniae, patient demographics and the susceptibilities of these bacteria to various antimicrobial agents were described. A total of 87.3% of isolates carried several bla genes. The prevalence of bla(CTX-M) was strikingly high: 99.6% for ESBL-producing E. coli (CTX-M-14, -15, -27, -40, and -55) and 99.2% for ESBL-producing K. pneumoniae (CTX-M-3, -14, -15, -27, and -55). ISEcp1 was found in the upstream region of bla(CTX-M) in most isolates. Up to 77.0% and 71.7% of ESBL-producing E. coli and ESBL-producing K. pneumoniae, respectively, carried bla(TEM); all of them encoded TEM-1. ESBL-producing K. pneumoniae carried bla(SHV) at 87.4% (SHV-1, -2a, -11, -12, -27, -71, and -75) but only at 3.8% for ESBL-producing E. coli (SHV-11 and -12). bla genes encoding VEB-1 and OXA-10 were found in both ESBL-producing E. coli (8.5% and 8.1%, respectively) and ESBL-producing K. pneumoniae (10.2% and 11.8%, respectively). None of the isolates were positive for bla(PER) and bla(GES). Pulsed-field gel electrophoresis analysis demonstrated that there was no major clonal relationship among these ESBL producers. This is the first study to report CTX-M-3, CTX-M-27, CTX-M-40, SHV-27, SHV-71, and SHV-75 in Thailand and to show that CTX-M ESBL is highly endemic in the country.

A systematic literature review and meta-analysis of the burden of healthcare-associated infections (HAIs) in Southeast Asia was performed on 41 studies out of the initially identified 14 089 records. The pooled prevalence of overall HAIs was 9.0% (95% confidence interval [CI], 7.2%-10.8%), whereas the pooled incidence density of HAI was 20 cases per 1000 intensive care unit-days. The pooled incidence density of ventilator-associated pneumonia, central line-associated bloodstream infection, and catheter-associated urinary tract infection was 14.7 per 1000 ventilator-days (95% CI, 11.7-17.7), 4.7 per 1000 catheter-days (95% CI, 2.9-6.5), and 8.9 per 1000 catheter-days (95% CI, 6.2-11.7), respectively. The pooled incidence of surgical site infection was 7.8% (95% CI, 6.3%-9.3%). The attributed mortality and excess length of stay in hospitals of infected patients ranged from 7% to 46% and 5 to 21 days, respectively.

Intra-abdominal infections (IAI) are an important cause of morbidity and are frequently associated with poor prognosis, particularly in high-risk patients. The cornerstones in the management of complicated IAIs are timely effective source control with appropriate antimicrobial therapy. Empiric antimicrobial therapy is important in the management of intra-abdominal infections and must be broad enough to cover all likely organisms because inappropriate initial antimicrobial therapy is associated with poor patient outcomes and the development of bacterial resistance. The overuse of antimicrobials is widely accepted as a major driver of some emerging infections (such as C. difficile), the selection of resistant pathogens in individual patients, and for the continued development of antimicrobial resistance globally. The growing emergence of multi-drug resistant organisms and the limited development of new agents available to counteract them have caused an impending crisis with alarming implications, especially with regards to Gram-negative bacteria. An international task force from 79 different countries has joined this project by sharing a document on the rational use of antimicrobials for patients with IAIs. The project has been termed AGORA (Antimicrobials: A Global Alliance for Optimizing their Rational Use in Intra-Abdominal Infections). The authors hope that AGORA, involving many of the world's leading experts, can actively raise awareness in health workers and can improve prescribing behavior in treating IAIs.

OBJECTIVES: To investigate the prevalence of the vacA, cagA, cagE, iceA, and babA2 genotypes in Helicobacter pylori strains isolated from Thai dyspeptic patients, and to determine whether any correlation exists between these genotypes and clinical manifestations. METHODS: Helicobacter pylori was examined in 112 patients (62 with non-ulcer dyspepsia (gastritis), 34 with peptic ulcer disease, and 16 with gastric cancer (GCA)), detected by culture or direct detection from gastric biopsies. Allelic variants of the vacA, cagA, cagE, iceA, and babA2 genotypes were identified by using the polymerase chain reaction. RESULTS: The positive rates for the vacAs1, vacAs2, cagA, cagE, iceA1, iceA2, and babA2 genes in H. pylori of dyspeptic patients were 100%, 0%, 98.2%, 88.4%, 45.5%, 33.1%, and 92%, respectively. The allelic variant vacAs1m1 was more prevalent (58%) than vacAs1m2 (42%). The cagA and cagE genes were commonly found together (87.5%). The most predominant genotypes were vacAs1m1, cagA, cagE, iceA1, and babA2. The various genes alone or in combination had no statistically significant association with the clinical outcomes (p>0.05). CONCLUSION: Neither single gene nor combination of vacA, cagA, cagE, iceA, and babA2 genes was significantly helpful in predicting the clinical outcome of H. pylori infection in Thai patients. The high prevalence of these genes in H. pylori isolated from Thai patient groups suggests that H. pylori strains are geographically dependent.

OBJECTIVES: To comprehensively compare and rank the efficacy and safety of available treatment options for patients with MDR and XDR Acinetobacter baumannii (AB) infection. METHODS: We searched PubMed, Embase and the Cochrane register of trials systematically for studies that examined treatment options for patients with MDR- and XDR-AB infections until April 2016. Network meta-analysis (NMA) was performed to estimate the risk ratio (RR) and 95% CI from both direct and indirect evidence. Primary outcomes were clinical cure and microbiological cure. Secondary outcomes were all-cause mortality and nephrotoxic and non-nephrotoxic adverse events. RESULTS: A total of 29 studies with 2529 patients (median age 60 years; 65% male; median APACHE II score 19.0) were included. Although there were no statistically significant differences between treatment options, triple therapy with colistin, sulbactam and tigecycline had the highest clinical cure rate. Colistin in combination with sulbactam was associated with a significantly higher microbiological cure rate compared with colistin in combination with tigecycline (RR 1.23; 95% CI 1.03-1.47) and colistin monotherapy (RR 1.21; 95% CI 1.06-1.38). No significant differences in all-cause mortality were noted between treatment options. Tigecycline-based therapy also appeared less effective for achieving a microbiological cure and is not appropriate for treating bloodstream MDR- and XDR-AB infections. CONCLUSIONS: Combination therapy of colistin with sulbactam demonstrates superiority in terms of microbiological cure with a safety profile similar to that of colistin monotherapy. Thus, our findings support the use of this combination as a treatment for MDR- and XDR-AB infections.

BACKGROUND: We conducted a study to evaluate the impact of education and an antibiotic-control program on antibiotic-prescribing practices, antibiotic consumption, antimicrobial resistance, and cost of antibiotics in a tertiary care hospital in Thailand. METHODS: A study of the year before and the year after the intervention was performed. Inpatient antibiotic prescriptions were prospectively observed. Demographic characteristics, hospital unit, indication for antibiotic prescription, appropriateness of antibiotic use, reasons for inappropriate antibiotic use, antibiotic consumption (i.e., the rate of antibiotic use), bacterial resistance, and antibiotic cost data were collected. Interventions included education, introduction of an antibiogram, use of antibiotic prescription forms, and prescribing controls. RESULTS: After the intervention, there was a 24% reduction in the rate of antibiotic prescription (640 vs. 400 prescriptions/1000 admissions; P<.001). The incidence of inappropriate antibiotic use was significantly reduced (42% vs. 20%; P<.001). A sustained reduction in antibiotic use was observed (R2=0.692; P<.001). Rates of use of third-generation cephalosporins (31 vs. 18 defined daily doses [DDDs]/1000 patient-days; P<.001) and glycopeptides (3.2 vs. 2.4 DDDs/1000 patient-days; P=.002) were significantly reduced. Rates of use of cefazolin (3.5 vs. 8.2 DDDs/1000 patient-days; P<.001) and fluoroquinolones (0.68 vs. 1.15 DDDs/1000 patient-days; P<.001) increased. There were no significant changes for other antibiotic classes. Significant reductions in the incidence of infections due to methicillin-resistant Staphylococcus aureus (48% vs. 33.5%; P<.001), extended-spectrum beta -lactamase-producing Escherichia coli (33% vs. 21%; P<.001), extended-spectrum beta -lactamase-producing Klebsiella pneumoniae (30% vs. 20%; P<.001), and third-generation cephalosporin-resistant Acinetobacter baumanii (27% vs. 19%; P<.001) were also observed. Total costs saving were USD 32,231 during the study period. CONCLUSIONS: Education and an antibiotic-control program constituted an effective and cost-saving strategy to optimize antibiotic use in a tertiary care center in Thailand.

Antimicrobial resistance is a global public health crisis. Antimicrobial Stewardship involves adopting systematic measures to optimize antimicrobial use, decrease unnecessary antimicrobial exposure and to decrease the emergence and spread of resistance. Low- and middle-income countries (LMICs) face a disproportionate burden of antimicrobial resistance and also face challenges related to resource availability. Although challenges exist, the World Health Organization has created a practical toolkit for developing Antimicrobial Stewardship Programs (ASPs) that will be summarized in this article.

Background: The Asia Pacific Society of Infection Control (APSIC) launched the APSIC Guidelines for the Prevention of Surgical Site Infections in 2018. This document describes the guidelines and recommendations for the setting prevention of surgical site infections (SSIs). It aims to highlight practical recommendations in a concise format designed to assist healthcare facilities at Asia Pacific region in achieving high standards in preoperative, perioperative and postoperative practices. Method: The guidelines were developed by an appointed workgroup comprising experts in the Asia Pacific region, following reviews of previously published guidelines and recommendations relevant to each section. Results: It recommends that healthcare facilities review specific risk factors and develop effective prevention strategies, which would be cost effective at local levels. Gaps identified are best closed using a quality improvement process. Surveillance of SSIs is recommended using accepted international methodology. The timely feedback of the data analysed would help in the monitoring of effective implementation of interventions. Conclusions: Healthcare facilities should aim for excellence in safe surgery practices. The implementation of evidence-based practices using a quality improvement process helps towards achieving effective and sustainable results.

PURPOSE OF REVIEW: Several viral diseases have emerged and impacted healthcare systems worldwide. Healthcare personnels (HCPs) are at high risk of acquiring some emerging infections while caring for patients. We provide a review of risk factors, evidence of infection in HCPs, and prevention strategies with Middle East respiratory syndrome coronavirus, Ebola virus disease (Ebola), severe acute respiratory syndrome (SARS), and avian influenza. RECENT FINDINGS: HCP-related infections with Middle East respiratory syndrome coronavirus, Ebola, and SARS have been reported among 1-27%, 2.5-12%, and 11-57% of total cases, respectively. The case fatality rate of Ebola in HCPs has been reported up to 73%. The WHO guidelines for the global surveillance of SARS were developed in 2004 and used as a template for other emerging diseases preparedness. Risks to HCPs with emerging diseases are related to inappropriate and insufficient infection control measures during an initial encounter, at the beginning of outbreak and with an overwhelming number of patient cases. To date, there are no reports of avian influenza transmission to HCPs from affected cases. SUMMARY: Early and rapid detection of suspected infected patients with communicable diseases along with appropriate infection control practice, education, national and global preparedness guidelines would help to prevent disease transmission to HCPs.

OBJECTIVE: To report the results of a surveillance study on surgical site infections (SSIs) conducted by the International Nosocomial Infection Control Consortium (INICC). DESIGN: Cohort prospective multinational multicenter surveillance study. SETTING: Eighty-two hospitals of 66 cities in 30 countries (Argentina, Brazil, Colombia, Cuba, Dominican Republic, Egypt, Greece, India, Kosovo, Lebanon, Lithuania, Macedonia, Malaysia, Mexico, Morocco, Pakistan, Panama, Peru, Philippines, Poland, Salvador, Saudi Arabia, Serbia, Singapore, Slovakia, Sudan, Thailand, Turkey, Uruguay, and Vietnam) from 4 continents (America, Asia, Africa, and Europe). PATIENTS: Patients undergoing surgical procedures (SPs) from January 2005 to December 2010. METHODS: Data were gathered and recorded from patients hospitalized in INICC member hospitals by using the methods and definitions of the Centers for Disease Control and Prevention National Healthcare Safety Network (CDC-NHSN) for SSI. SPs were classified into 31 types according to International Classification of Diseases, Ninth Revision, criteria. RESULTS: We gathered data from 7,523 SSIs associated with 260,973 SPs. SSI rates were significantly higher for most SPs in INICC hospitals compared with CDC-NHSN data, including the rates of SSI after hip prosthesis (2.6% vs. 1.3%; relative risk [RR], 2.06 [95% confidence interval (CI), 1.8-2.4]; P < .001), coronary bypass with chest and donor incision (4.5% vs. 2.9%; RR, 1.52 [95% CI, 1.4-1.6]; [P < .001); abdominal hysterectomy (2.7% vs. 1.6%; RR, 1.66 [95% CI, 1.4-2.0]; P < .001); exploratory abdominal surgery (4.1% vs. 2.0%; RR, 2.05 [95% CI, 1.6-2.6]; P < .001); ventricular shunt, 12.9% vs. 5.6% (RR, 2.3 [95% CI, 1.9-2.6]; P < .001, and others. CONCLUSIONS: SSI rates were higher for most SPs in INICC hospitals compared with CDC-NHSN data.

BACKGROUND: This study evaluated the relative efficacy of strategies for the prevention of multidrug-resistant gram-negative bacteria (MDR-GNB) in adult intensive care units (ICUs). METHODS: A systematic review and network meta-analysis was performed; searches of the Cochrane Library, PubMed, Embase, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) included all randomized controlled trials and observational studies conducted in adult patients hospitalized in ICUs and evaluating standard care (STD), antimicrobial stewardship program (ASP), environmental cleaning (ENV), decolonization methods (DCL), or source control (SCT), simultaneously. The primary outcomes were MDR-GNB acquisition, colonization, and infection; secondary outcome was ICU mortality. RESULTS: Of 3805 publications retrieved, 42 met inclusion criteria (5 randomized controlled trials and 37 observational studies), involving 62068 patients (median age, 58.8 years; median APACHE [Acute Physiology and Chronic Health Evaluation] II score, 18.9). The majority of studies reported extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae and MDR Acinetobacter baumannii. Compared with STD, a 4-component strategy composed of STD, ASP, ENV, and SCT was the most effective intervention (rate ratio [RR], 0.05 [95% confidence interval {CI}, .01-.38]). When ENV was added to STD+ASP or SCT was added to STD+ENV, there was a significant reduction in the acquisition of MDR A. baumannii (RR, 0.28 [95% CI, .18-.43] and 0.48 [95% CI, .35-.66], respectively). Strategies with ASP as a core component showed a statistically significant reduction the acquisition of ESBL-producing Enterobacteriaceae (RR, 0.28 [95% CI, .11-.69] for STD+ASP+ENV and 0.23 [95% CI, .07-.80] for STD+ASP+DCL). CONCLUSIONS: A 4-component strategy was the most effective intervention to prevent MDR-GNB acquisition. As some strategies were differential for certain bacteria, our study highlighted the need for further evaluation of the most effective prevention strategies.

We report the first case of avian influenza in a patient with fever and diarrhea but no respiratory symptoms. Avian influenza should be included in the differential diagnosis for patients with predominantly gastrointestinal symptoms, particularly if they have a history of exposure to poultry.

Helicobacter pylori (H. pylori) infection remains to be the major cause of important upper gastrointestinal diseases such as chronic gastritis, peptic ulcer, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. H. pylori management in ASEAN: the Bangkok consensus report gathered key opinion leaders for the region to review and evaluate clinical aspects of H. pylori infection and to develop consensus statements, rationales, and grades of recommendation for the management of H. pylori infection in clinical practice in ASEAN countries. This ASEAN Consensus consisted of 34 international experts from 10 ASEAN countries, Japan, Taiwan, and the United States. The meeting mainly focused on four issues: (i) epidemiology and disease association; (ii) diagnostic tests; (iii) management; and (iv) follow-up after eradication. The final results of each workshop were presented for consensus voting by all participants. Statements, rationale, and recommendations were developed from the available current evidence to help clinicians in the diagnosis and treatment of H. pylori and its clinical diseases.

BACKGROUND/AIMS: Environmental factors such as food, lifestyle and prevalence of Helicobacter pylori infection are widely different in Asian countries compared to the West, and physiological functions and genetic factors of Asians may also be different from those of Westerners. Establishing an Asian consensus for functional dyspepsia is crucial in order to attract attention to such data from Asian countries, to articulate the experience and views of Asian experts, and to provide a relevant guide on management of functional dyspepsia for primary care physicians working in Asia. METHODS: Consensus team members were selected from Asian experts and consensus development was carried out using a modified Delphi method. Consensus teams collected published papers on functional dyspepsia especially from Asia and developed candidate consensus statements based on the generated clinical questions. At the first face-to-face meeting, each statement was reviewed and e-mail voting was done twice. At the second face-to-face meeting, final voting on each statement was done using keypad voting system. A grade of evidence and a strength of recommendation were applied to each statement according to the method of the GRADE Working Group. RESULTS: Twenty-nine consensus statements were finalized, including 7 for definition and diagnosis, 5 for epidemiology, 9 for pathophysiology and 8 for management. Algorithms for diagnosis and management of functional dyspepsia were added. CONCLUSIONS: This consensus developed by Asian experts shows distinctive features of functional dyspepsia in Asia and will provide a guide to the diagnosis and management of functional dyspepsia for Asian primary care physicians.