The Pediatric Infectious Disease Journal • Volume 34, Number 4, April 2015
Brown et al
threat. It increases the cost of therapy and mortality rate. Continuous surveillance is required and strict infectious control practices must be adopted. It is also important to revise the empirical therapy regimen and antibiotic administration policy at hospitals. REFERENCES 1. Black RE, Cousens S, Johnson HL, et al; Child Health Epidemiology Reference Group of WHO and UNICEF. Global, regional, and national causes of child mortality in 2008: a systematic analysis. Lancet. 2010;375:1969–1987. 2. Nahid F, Khan AA, Rehman S, et al. Prevalence of metallo-beta-lactamase NDM-1-producing multi-drug resistant bacteria at two Pakistani hospitals and implications for public health. J Infect Public Health. 2013;6:487–493. 3. Perry JD, Naqvi SH, Mirza IA, et al. Prevalence of faecal carriage of Enterobacteriaceae with NDM-1 carbapenemase at military hospitals in Pakistan, and evaluation of two chromogenic media. J Antimicrob Chemother. 2011;66:2288–2294. 4. Pérez-Pérez FJ, Hanson ND. Detection of plasmid-mediated AmpC beta-lactamase genes in clinical isolates by using multiplex PCR. J Clin Microbiol. 2002;40:2153–2162. 5. Woodford N, Fagan EJ, Ellington MJ. Multiplex PCR for rapid detection of genes encoding CTX-M extended-spectrum (beta)-lactamases. J Antimicrob Chemother. 2006;57:154–155. 6. Day KM, Pike R, Winstanley TG, et al. Use of faropenem as an indicator of carbapenemase activity in the Enterobacteriaceae. J Clin Microbiol. 2013;51:1881–1886. 7. Kasbekar N. Tigecycline: a new glycylcycline antimicrobial agent. Am J Health Syst Pharm. 2006;63:1235–1243. 8. Livermore DM. Tigecycline: what is it, and where should it be used? J Antimicrob Chemother. 2005;56:611–614. 9. Mehta M, Dutta P, Gupta V. Antimicrobial susceptibility pattern of blood isolates from a teaching hospital in north India. Jpn J Infect Dis. 2005;58:174–176. 10. Rahman MM, Haq JA, Hossain MA, et al. Prevalence of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in an urban hospital in Dhaka, Bangladesh. Int J Antimicrob Agents. 2004;24:508–510.
STAPHYLOCOCCUS AUREUS RETROPHARYNGEAL ABSCESS IN CHILDREN Nicholas K. Brown, BA, Kristina G. Hulten, PhD, Edward O. Mason, PhD, and Sheldon L. Kaplan, MD Abstract: A retrospective review of 33 patients comparing community-associated methicillin-resistant Staphylococcus aureus retropharyngeal abscess (RPA) with community-associated methicillin-susceptible S. aureus RPA from 2002–2013 at Texas Children’s Hospital revealed most cases of S. aureus RPA have been due to community-associated methicillin-resistant S. aureus, which appears to be associated with a more complicated clinical course than RPA caused by community-associated methicillin-susceptible S. aureus. Key Words: Retropharyngeal abscess, methicillin-resistant Staphylococcus aureus, USA300, children From the Section of Infectious Diseases, Department of Pediatrics, Baylor College of Medicine and Texas Children’s Hospital, Houston, Texas. Sources of prior support: Pfizer. The authors have no other conflicts of interest or funding to disclose. Address for correspondence: Sheldon L. Kaplan, MD, Texas Children’s Hospital, Feigin Center, Suite 1150, 1102 Bates, Houston, TX 77030. E-mail: [email protected]. Copyright © 2014 by Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/INF.0000000000000599
I
n children, 2 chains of lymph nodes are located in the retropharyngeal space, that usually involute by age 5 or 6 years old.1 These lymph nodes drain areas of the nose and nasopharynx and are subject
454 | www.pidj.com
to suppuration and subsequent abscess formation. Retropharyngeal abscesses (RPAs) formed by this pathogenesis are often idiopathic, but may be preceded by a bacterial/viral upper respiratory infection or oral-pharyngeal trauma, especially in older children.2 During the past 20 years, the frequency of both community-associated methicillin-resistant Staphylococcus aureus (CAMRSA) infections and RPA has increased in the United States.3–6 Recent reports have suggested that RPA due to CA-MRSA appears to be associated with a more complicated clinical course than RPA due to other bacteria.5 At Texas Children’s Hospital (TCH), methicillin-resistant S. aureus (MRSA) accounts for over half of the S. aureus infections with onset in the community occurring in normal children.7 We compared the clinical course of patients at TCH with RPA caused by MRSA versus methicillin-susceptible S. aureus (MSSA), including the molecular characteristics of these isolates collected at the time of surgery.
MATERIALS AND METHODS Patients This was a retrospective observational study of children identified in the TCH Pediatric Infectious Diseases S. aureus surveillance study database with positive cultures for S. aureus taken at the time of surgical drainage of RPA from July 2002 to May 2013.7 Data were not collected for children with RPA due to other bacteria. Patient’s demographic data, presenting signs and symptoms, radiographic imaging, complications, treatment and outcome were obtained from the medical record and recorded on a case report form. Fever was defined as greater than 38°C (100.4°F). This study was approved by the institutional review board of Baylor College of Medicine.
Laboratory Methods S. aureus was isolated by the TCH clinical microbiology laboratory from purulent material drained from the RPA, and antibiotic susceptibilities were determined using standard methods. Isolates were retrieved from the microbiology laboratory and stored frozen at −80°F in the Infectious Diseases Research Laboratory at TCH for further studies. The isolates were analyzed by pulsed field gel electrophoresis.8
Statistical Analysis Dichotomous variables were examined with the χ2 and Fisher exact tests, and continuous variables were analyzed with a Mann– Whitney U test using Stata 12 (Statacorp, College Station, TX). Twotailed P-values 7 years of age, presented after hearing a popping sound while stretching his neck. No other children presented with a history of trauma. Symptoms at presentation included fever (88%), neck swelling (52%), limited range of motion of the neck (42%), neck stiffness (18%), palpable neck pain (18%), drooling (18%), dysphagia (15%) and change in voice quality (12%). On physical examination, the most common findings were cervical lymphadenopathy (45%), swelling of posterior pharynx (42%), respiratory distress (33%), stridor (30%), torticollis (12%) and trismus (6%). The median white blood cell count was 18,800/uL (range, 4900– 37,900/μL) with a median erythrocyte sedimentation rate and © 2014 Wolters Kluwer Health, Inc. All rights reserved.
The Pediatric Infectious Disease Journal • Volume 34, Number 4, April 2015
C-reactive protein of 46 mm/h (range, 36–96 mm/h) and 5.9 mg/ dL (range, 1.25–24.6 mg/dL), respectively. Computed tomography scan of the neck with contrast was performed on all 33 patients. The most common findings included low-density core (88%), mass effect (76%), rim enhancement (55%), soft-tissue swelling (42%) and parapharyngeal involvement (40%). Seven patients (21%) had evidence of mediastinitis. Computed tomography scan for 1 child (3%) showed evidence of a thrombus. Empiric antibiotics consisted of intravenous clindamycin in 25 (76%), vancomycin in 16 (48%), cefotaxime/ceftriaxone in 14 (42%) and gentamicin in 2 (6%) either alone or in combination with the others. Vancomycin was included for patients presenting with complications such as mediastinitis and respiratory distress from airway obstruction. Surgery was performed on all 33 patients through a transoral approach with incision and drainage. Purulent material was obtained from all patients and was found to be positive for MRSA in 26 (79%); 7 (21%) of the total 33 patients had polymicrobial infections. There was an apparent trend toward increasing frequency of S. aureus RPA in the last 10 years at TCH. Out of the 33 S. aureus isolates, 26 (79%) were USA300, 5 (15%) were non-USA300 and 2 were not available for testing. There were no statistically significant differences between the patients with polymicrobial infections versus those with S. aureus alone with respect to age, complications or treatment with multiple antibiotics. The median duration of intravenous antibiotic therapy was 4.5 days (range, 2–12 days) with most patients (79%) being discharged home on oral clindamycin for a median total duration of antibiotic therapy of 13 days (range, 11–17 days). Five (15%) patients completed therapy with trimethoprim– sulfamethoxazole. Eight patients (24%) presented with airway obstruction, 7 (21%) had mediastinitis, 2 (6%) needed multiple surgeries and 2 (6%) had thromboses (1 deep venous thrombosis, 1 Lemierre syndrome). Blood cultures were obtained from 24 patients; 1 was positive for MRSA. One patient had an especially complicated course with mediastinitis, emergency intubation and Lemierre syndrome requiring resection of the internal jugular vein, mastoidectomy, craniectomy and 7th cranial nerve decompression. All patients survived and recovered well without sequelae on follow-up. Three clinical characteristics differed significantly between MRSA and MSSA patients. In the MRSA group, median duration of admission was 5.5 versus 3 days for MSSA (p = 0.05), median duration of intravenous antibiotic therapy was 6 versus 3 days for MSSA (P = 0.009) and percentage of patients
Brown et al
threat. It increases the cost of therapy and mortality rate. Continuous surveillance is required and strict infectious control practices must be adopted. It is also important to revise the empirical therapy regimen and antibiotic administration policy at hospitals. REFERENCES 1. Black RE, Cousens S, Johnson HL, et al; Child Health Epidemiology Reference Group of WHO and UNICEF. Global, regional, and national causes of child mortality in 2008: a systematic analysis. Lancet. 2010;375:1969–1987. 2. Nahid F, Khan AA, Rehman S, et al. Prevalence of metallo-beta-lactamase NDM-1-producing multi-drug resistant bacteria at two Pakistani hospitals and implications for public health. J Infect Public Health. 2013;6:487–493. 3. Perry JD, Naqvi SH, Mirza IA, et al. Prevalence of faecal carriage of Enterobacteriaceae with NDM-1 carbapenemase at military hospitals in Pakistan, and evaluation of two chromogenic media. J Antimicrob Chemother. 2011;66:2288–2294. 4. Pérez-Pérez FJ, Hanson ND. Detection of plasmid-mediated AmpC beta-lactamase genes in clinical isolates by using multiplex PCR. J Clin Microbiol. 2002;40:2153–2162. 5. Woodford N, Fagan EJ, Ellington MJ. Multiplex PCR for rapid detection of genes encoding CTX-M extended-spectrum (beta)-lactamases. J Antimicrob Chemother. 2006;57:154–155. 6. Day KM, Pike R, Winstanley TG, et al. Use of faropenem as an indicator of carbapenemase activity in the Enterobacteriaceae. J Clin Microbiol. 2013;51:1881–1886. 7. Kasbekar N. Tigecycline: a new glycylcycline antimicrobial agent. Am J Health Syst Pharm. 2006;63:1235–1243. 8. Livermore DM. Tigecycline: what is it, and where should it be used? J Antimicrob Chemother. 2005;56:611–614. 9. Mehta M, Dutta P, Gupta V. Antimicrobial susceptibility pattern of blood isolates from a teaching hospital in north India. Jpn J Infect Dis. 2005;58:174–176. 10. Rahman MM, Haq JA, Hossain MA, et al. Prevalence of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in an urban hospital in Dhaka, Bangladesh. Int J Antimicrob Agents. 2004;24:508–510.
STAPHYLOCOCCUS AUREUS RETROPHARYNGEAL ABSCESS IN CHILDREN Nicholas K. Brown, BA, Kristina G. Hulten, PhD, Edward O. Mason, PhD, and Sheldon L. Kaplan, MD Abstract: A retrospective review of 33 patients comparing community-associated methicillin-resistant Staphylococcus aureus retropharyngeal abscess (RPA) with community-associated methicillin-susceptible S. aureus RPA from 2002–2013 at Texas Children’s Hospital revealed most cases of S. aureus RPA have been due to community-associated methicillin-resistant S. aureus, which appears to be associated with a more complicated clinical course than RPA caused by community-associated methicillin-susceptible S. aureus. Key Words: Retropharyngeal abscess, methicillin-resistant Staphylococcus aureus, USA300, children From the Section of Infectious Diseases, Department of Pediatrics, Baylor College of Medicine and Texas Children’s Hospital, Houston, Texas. Sources of prior support: Pfizer. The authors have no other conflicts of interest or funding to disclose. Address for correspondence: Sheldon L. Kaplan, MD, Texas Children’s Hospital, Feigin Center, Suite 1150, 1102 Bates, Houston, TX 77030. E-mail: [email protected]. Copyright © 2014 by Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/INF.0000000000000599
I
n children, 2 chains of lymph nodes are located in the retropharyngeal space, that usually involute by age 5 or 6 years old.1 These lymph nodes drain areas of the nose and nasopharynx and are subject
454 | www.pidj.com
to suppuration and subsequent abscess formation. Retropharyngeal abscesses (RPAs) formed by this pathogenesis are often idiopathic, but may be preceded by a bacterial/viral upper respiratory infection or oral-pharyngeal trauma, especially in older children.2 During the past 20 years, the frequency of both community-associated methicillin-resistant Staphylococcus aureus (CAMRSA) infections and RPA has increased in the United States.3–6 Recent reports have suggested that RPA due to CA-MRSA appears to be associated with a more complicated clinical course than RPA due to other bacteria.5 At Texas Children’s Hospital (TCH), methicillin-resistant S. aureus (MRSA) accounts for over half of the S. aureus infections with onset in the community occurring in normal children.7 We compared the clinical course of patients at TCH with RPA caused by MRSA versus methicillin-susceptible S. aureus (MSSA), including the molecular characteristics of these isolates collected at the time of surgery.
MATERIALS AND METHODS Patients This was a retrospective observational study of children identified in the TCH Pediatric Infectious Diseases S. aureus surveillance study database with positive cultures for S. aureus taken at the time of surgical drainage of RPA from July 2002 to May 2013.7 Data were not collected for children with RPA due to other bacteria. Patient’s demographic data, presenting signs and symptoms, radiographic imaging, complications, treatment and outcome were obtained from the medical record and recorded on a case report form. Fever was defined as greater than 38°C (100.4°F). This study was approved by the institutional review board of Baylor College of Medicine.
Laboratory Methods S. aureus was isolated by the TCH clinical microbiology laboratory from purulent material drained from the RPA, and antibiotic susceptibilities were determined using standard methods. Isolates were retrieved from the microbiology laboratory and stored frozen at −80°F in the Infectious Diseases Research Laboratory at TCH for further studies. The isolates were analyzed by pulsed field gel electrophoresis.8
Statistical Analysis Dichotomous variables were examined with the χ2 and Fisher exact tests, and continuous variables were analyzed with a Mann– Whitney U test using Stata 12 (Statacorp, College Station, TX). Twotailed P-values 7 years of age, presented after hearing a popping sound while stretching his neck. No other children presented with a history of trauma. Symptoms at presentation included fever (88%), neck swelling (52%), limited range of motion of the neck (42%), neck stiffness (18%), palpable neck pain (18%), drooling (18%), dysphagia (15%) and change in voice quality (12%). On physical examination, the most common findings were cervical lymphadenopathy (45%), swelling of posterior pharynx (42%), respiratory distress (33%), stridor (30%), torticollis (12%) and trismus (6%). The median white blood cell count was 18,800/uL (range, 4900– 37,900/μL) with a median erythrocyte sedimentation rate and © 2014 Wolters Kluwer Health, Inc. All rights reserved.
The Pediatric Infectious Disease Journal • Volume 34, Number 4, April 2015
C-reactive protein of 46 mm/h (range, 36–96 mm/h) and 5.9 mg/ dL (range, 1.25–24.6 mg/dL), respectively. Computed tomography scan of the neck with contrast was performed on all 33 patients. The most common findings included low-density core (88%), mass effect (76%), rim enhancement (55%), soft-tissue swelling (42%) and parapharyngeal involvement (40%). Seven patients (21%) had evidence of mediastinitis. Computed tomography scan for 1 child (3%) showed evidence of a thrombus. Empiric antibiotics consisted of intravenous clindamycin in 25 (76%), vancomycin in 16 (48%), cefotaxime/ceftriaxone in 14 (42%) and gentamicin in 2 (6%) either alone or in combination with the others. Vancomycin was included for patients presenting with complications such as mediastinitis and respiratory distress from airway obstruction. Surgery was performed on all 33 patients through a transoral approach with incision and drainage. Purulent material was obtained from all patients and was found to be positive for MRSA in 26 (79%); 7 (21%) of the total 33 patients had polymicrobial infections. There was an apparent trend toward increasing frequency of S. aureus RPA in the last 10 years at TCH. Out of the 33 S. aureus isolates, 26 (79%) were USA300, 5 (15%) were non-USA300 and 2 were not available for testing. There were no statistically significant differences between the patients with polymicrobial infections versus those with S. aureus alone with respect to age, complications or treatment with multiple antibiotics. The median duration of intravenous antibiotic therapy was 4.5 days (range, 2–12 days) with most patients (79%) being discharged home on oral clindamycin for a median total duration of antibiotic therapy of 13 days (range, 11–17 days). Five (15%) patients completed therapy with trimethoprim– sulfamethoxazole. Eight patients (24%) presented with airway obstruction, 7 (21%) had mediastinitis, 2 (6%) needed multiple surgeries and 2 (6%) had thromboses (1 deep venous thrombosis, 1 Lemierre syndrome). Blood cultures were obtained from 24 patients; 1 was positive for MRSA. One patient had an especially complicated course with mediastinitis, emergency intubation and Lemierre syndrome requiring resection of the internal jugular vein, mastoidectomy, craniectomy and 7th cranial nerve decompression. All patients survived and recovered well without sequelae on follow-up. Three clinical characteristics differed significantly between MRSA and MSSA patients. In the MRSA group, median duration of admission was 5.5 versus 3 days for MSSA (p = 0.05), median duration of intravenous antibiotic therapy was 6 versus 3 days for MSSA (P = 0.009) and percentage of patients
