2015 HSC Section 1 Book of Articles

The Pediatric Infectious Disease Journal •  Volume 33, Number 10, October 2014

Olarte et al

Denmark; Daco, Inc, Carpinteria, CA) in the Infectious Disease Research Laboratory. Antimicrobial susceptibility testing for penicillin and ceftri- axone was performed by standard microbroth dilution with Muel- ler-Hinton media supplemented with 3% lysed horse blood in the Infectious Disease Research Laboratory. Susceptibilities for eryth- romycin, clindamycin and trimethoprim-sulfamethoxazole were determined by standard disk diffusion testing in the TCH Clinical Microbiology Laboratory. Susceptibility categories were “suscepti- ble,” “intermediate” or “resistant” as defined by the 2012 Clinical and Laboratory Standards Institute. 15 Demographic and clinical information was collected retro- spectively and recorded on a case report form. Administration of PCV7 or PCV13 was documented through the medical records or by contacting the patient’s healthcare provider. We defined the prevaccine period as August 2008 through December 2010 (29 months). We defined the postvaccine period as January 2011 through December 2013 (36 months). PCV13 was licensed in the United States in February 2010, overlapping the endmost part of the prevaccine period; however, patients included in the prevaccine period had not received any PCV13 doses. To estimate the proportion of chronic sinusitis cases attrib- utable to S. pneumoniae, we used ICD-9 ( International Classifica- tion of Diseases, 9th Revision ) codes to identify the total number of patients with chronic sinusitis (ICD-9 code 473) who under- went ESS (ICD-9 code 31231 or 31000) during the study period. Descriptive statistics were used to characterize the study popula- tion. The χ 2 test and Fisher’s exact test were used to compare the characteristics of patients with chronic sinusitis before and after introduction of PCV13. IBM SPSS statistics V22.0.0 was the statis- tical program used. P ≤ 0.05 was considered significant. period and 407 in the post-PCV13 period) with chronic sinusitis who underwent ESS were identified based on ICD-9 codes. Of these, 91 of 652 (14%) had a positive sinus culture for S. pneumo- niae ; 55 of 245 (22%) and 36 of 407 (9%) were identified in the pre- and post-PCV13 periods, respectively ( P < 0.0001). The total number of annual pneumococcal sinusitis cases was: 19 in 2009; 26 in 2010; 11 in 2011; 20 in 2012 and only 5 in 2013. The median age of the patients was 24 months (range: 5 months to 17 years). Sixty-one (67%) patients were male. No differ- ences were noted in the age distribution and gender of the patients in the pre and postvaccine periods. Fifty-nine (65%) patients were white. All the patients presented with chronic nasal congestion/ drainage and chronic cough. Information regarding antibiotic ther- apy before surgery was only available in 43 patients (47%); of those 40 had received an antibiotic in the 4 weeks before surgery. The most common comorbid conditions were chronic oti- tis media (67%), allergic rhinitis (37%), reactive airway disease/ asthma (30%) and gastroesophageal reflux (15%). Of 91 patients, 23 (25%) had a significant underlying condition: 5 patients with cardiovascular disorder, 3 with central nervous system disorder, 3 with cystic fibrosis, 2 with Trisomy 21, 2 with malignancy, 2 with renal disorders and 1 each with Kartagener syndrome, Cri-du-chat, status post lung transplant secondary to bronchiolitis obliterans, Turner syndrome, juvenile osteochondrosis or thalassemia trait. No statistical difference in the type or frequency of comorbid or underlying medical conditions was observed between the pre- and post-PCV13 periods. Eleven (12%) patients had not received any doses of pneu- mococcal vaccine. Eighty (88%) patients received at least 1 dose of pneumococcal vaccine; of those 30 patients received at least 1 RESULTS During the study period, 652 patients (245 in the pre-PCV13

dose of PCV13. Seventy-two (79%) patients received 3 or more doses of pneumococcal vaccine; of those 14 patients received 3 or more doses of PCV13. No statistical difference was observed in the pneumococcal immunization status of the patients between the pre- and post-PCV13 periods. All 91 pneumococcal isolates were serotyped. Nineteen different serotypes were identified. Thirty isolates (33%) were PCV13 serotypes and 61 (67%) isolates were non-PCV13 serotypes. The percentage of PCV13 cases decreased 31% in the post-PCV13 era ( P = 0.003) when compared with the pre-PCV13 era (Fig. 1). This decrease was driven by a reduction of 27% of serotype 19A cases in the post-PCV13 period ( P = 0.007). No serotype 19A cases were identified in 2013. Serotype 19A (38%) and serotype 15C (17%) were the most common sero- types in the pre- and post-PCV13 periods, respectively (Table 1). All the cases in 2013 were because of non-PCV13 serotypes. Five patients developed sinusitis because of PCV13 sero- types (serotype 19A in 4 patients and serotype 3 in 1 patient) despite being fully immunized for S. pneumoniae by age includ- ing at least 1 PCV13 dose. Of these patients, 2 had an underlying condition: 1 patient had Trisomy 21 and Lennox-Gastaut syndrome and the other had asthma. All of the pneumococcal isolates were tested for antimi- crobial susceptibility. The percentages of isolates with penicillin minimal inhibitory concentration (MIC) ≥ 2 μ g/mL and ceftriaxone MIC ≥ 1 μ g/mLwere similar in the pre- and post-PCV13 periods. Sero- type 19A accounted for all the isolates with penicillin MIC ≥ 4 μ g/mL and ceftriaxone MIC ≥ 2 μ g/mL. Isolates with a penicillin MIC ≥ 2 μ g/mL and ceftriaxone MIC ≥ 1 μ g/mL were more com- monly associated with serotype 19A ( P < 0.001 for both). Clindamy- cin and trimethoprim-sulfamethoxazole nonsusceptibility also was seen more commonly in serotype 19A isolates ( P < 0.01 for both). Sixteen cases (18%) were positive for S. pneumoniae only and 75 cases (82%) represented polymicrobial infections. S. pneumoniae -only infections were not associated with any particu- lar pneumococcal serotype. The most common co-isolated organ- isms were nontypeable H. influenzae (52%), Moraxella catarrhalis (36%) and Staphylococcus aureus (11%; Table 2). Of the nontypea- ble H. influenzae isolates, 10 of 47 were β -lactamase positive.All M. catarrhalis isolates were β -lactamase positive with the exception of one. Three methicillin-resistant S. aureus isolates were identified. No specific age group was more affected by S. pneumoniae -only or

FIGURE 1.  Serotype distribution of pneumococcal isolates recovered from children undergoing endoscopic sinus surgery 2009–2013. PCV7-serotypes included in the 7-valent PCV; PCV13-serotypes included only in the 13-valent PCV; non-PCV13-serotypes not included in the 13-valent PCV.

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