Ming-Wei Cheng1, Chun-Ming Lee2, Nai-Yu Wang3, Alice Y Wu4, Chih-Chen Lin1, Li-Chuan Weng4, Chang-Pan Liu5, Shou-Chuan Shih6. 1. Division of Infectious Diseases, Department of Internal Medicine, MacKay Memorial Hospital, Taipei, Taiwan. 2. Division of Infectious Diseases, Department of Internal Medicine, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medicine, MacKay Medical College, New Taipei City, Taiwan; MacKay College of Medicine, Nursing and Management, Taipei, Taiwan; Infection Control Committee, MacKay Memorial Hospital, Taipei, Taiwan. 3. Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan. 4. Division of Infectious Diseases, Department of Internal Medicine, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan. 5. Division of Infectious Diseases, Department of Internal Medicine, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medicine, MacKay Medical College, New Taipei City, Taiwan; MacKay College of Medicine, Nursing and Management, Taipei, Taiwan; Infection Control Committee, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan. Electronic address: joeliu5929@hotmail.com.tw. 6. Department of Medicine, MacKay Medical College, New Taipei City, Taiwan; MacKay College of Medicine, Nursing and Management, Taipei, Taiwan; Infection Control Committee, MacKay Memorial Hospital, Taipei, Taiwan; Department of Medical Research, MacKay Memorial Hospital, Taipei, Taiwan; Division of Gastroenterology, Department of Internal Medicine, MacKay Memorial Hospital, Taipei, Taiwan. Electronic address: shihshou@gmail.com.
Abstract
BACKGROUND/ PURPOSE: The purpose of this study is to describe clinical characteristics of Salmonella bacteremia in adult patients and analyze ciprofloxacin-nonsusceptible isolates. METHODS: A total of 101 Salmonella blood isolates from adult patients were collected from January 2011 to December 2013 in MacKay Memorial Hospital. Eight ciprofloxacin-nonsusceptible Salmonella blood isolates were screened for carbapenemase and other β lactamase genes. Isolates were examined by PCR for the quinolone resistance-determining region (QRDR) of all subunits for DNA gyrase (gyrA and gyrB) genes and topoisomerase IV (parC and parE) genes. RESULTS: There were 22 (21.78%) S. enterica serovar B, 5 (4.95%) S. enterica serovar C1, 7 (6.93%) S. enterica serovar C2, 65 (64.36%) S. enterica serovar D, and 2 (1.98%) S. enterica serovar Typhi (S. typhi) isolates. β-lactamase gene screening and sequencing yielded only one blaCMY-2-positive isolate. In multivariate risk factor analysis, renal insufficiency [odds ratio (OR) 3.774; p = 0.020] and heart disease (OR 2.922; p = 0.027) were more common among elderly patients (≥65 years). Independent risk factors for ciprofloxacin-nonsusceptible strains included S. enterica serovar C2 (OR 28.430; p = 0.032), renal insufficiency (OR 13.927; p = 0.032), and immunosuppression agent usage (OR 60.082; p = 0.006). 87.50% (7/8) of isolates had gyrA mutation, 62.50% (5/8) had parC mutation, and none had gyrB and parE mutations. Isolates with both Ser83Phe/Asp87Asn gyrA and Thr57Ser/Ser80Ile parC mutation genes were highly ciprofloxacin-resistant (minimum inhibitory concentration ≥4 mg/L). CONCLUSIONS: Elderly patients with renal insufficiency and heart disease were at risk for Salmonella bacteremia. Those for ciprofloxacin-nonsusceptible strains included S. enterica serovar C2, renal insufficiency, and immunosuppression agent usage. The 8 ciprofloxacin-nonsusceptible isolates carried gyrA and parC mutations, which cause resistance that poses a major concern.
BACKGROUND/ PURPOSE: The purpose of this study is to describe clinical characteristics of Salmonella bacteremia in adult patients and analyze ciprofloxacin-nonsusceptible isolates. METHODS: A total of 101 Salmonella blood isolates from adult patients were collected from January 2011 to December 2013 in MacKay Memorial Hospital. Eight ciprofloxacin-nonsusceptible Salmonella blood isolates were screened for carbapenemase and other β lactamase genes. Isolates were examined by PCR for the quinolone resistance-determining region (QRDR) of all subunits for DNA gyrase (gyrA and gyrB) genes and topoisomerase IV (parC and parE) genes. RESULTS: There were 22 (21.78%) S. enterica serovar B, 5 (4.95%) S. enterica serovar C1, 7 (6.93%) S. enterica serovar C2, 65 (64.36%) S. enterica serovar D, and 2 (1.98%) S. enterica serovar Typhi (S. typhi) isolates. β-lactamase gene screening and sequencing yielded only one blaCMY-2-positive isolate. In multivariate risk factor analysis, renal insufficiency [odds ratio (OR) 3.774; p = 0.020] and heart disease (OR 2.922; p = 0.027) were more common among elderly patients (≥65 years). Independent risk factors for ciprofloxacin-nonsusceptible strains included S. enterica serovar C2 (OR 28.430; p = 0.032), renal insufficiency (OR 13.927; p = 0.032), and immunosuppression agent usage (OR 60.082; p = 0.006). 87.50% (7/8) of isolates had gyrA mutation, 62.50% (5/8) had parC mutation, and none had gyrB and parE mutations. Isolates with both Ser83Phe/Asp87Asn gyrA and Thr57Ser/Ser80Ile parC mutation genes were highly ciprofloxacin-resistant (minimum inhibitory concentration ≥4 mg/L). CONCLUSIONS: Elderly patients with renal insufficiency and heart disease were at risk for Salmonella bacteremia. Those for ciprofloxacin-nonsusceptible strains included S. enterica serovar C2, renal insufficiency, and immunosuppression agent usage. The 8 ciprofloxacin-nonsusceptible isolates carried gyrA and parC mutations, which cause resistance that poses a major concern.