Mario J. Marcon

Epidemiologic and Laboratory Features of a Large Outbreak of Pertussis-Like Illnesses Associated With Cocirculating Bordetella holmesii and Bordetella pertussis—Ohio, 2010–2011

BACKGROUNDnDuring 9 May 2010-7 May 2011, an outbreak of pertussis-like illness (incidence, 80 cases per 100 000 persons) occurred in Franklin County, Ohio. The majority of cases were identified by IS481-directed polymerase chain reaction (PCR), which does not differentiate among Bordetella species. We sought to determine outbreak etiology and epidemiologic characteristics.nnnMETHODSnWe obtained demographic, clinical, and vaccination-related data from the Ohio Disease Reporting System and Impact Statewide Immunization Information System. We tested sera from 14 patients for anti-pertussis toxin (PT) antibodies and used species-specific PCR on 298 nasopharyngeal specimens.nnnRESULTSnReported cases totaled 918. IS481 results were available for 10 serologically tested patients; 5 of 10 had discordant anti-PT antibody and IS481 results, suggestive of Bordetella holmesii, which lacks PT and harbors IS481. We identified specific Bordetella species in 164 of 298 specimens tested with multitarget PCR; B. holmesii and Bordetella pertussis were exclusively detected among 48 (29%) and 112 (68%), respectively; both were detected in 4 (2%). Among 48 patients with B. holmesii infections, 63% were aged 11-18 years, compared with 35% of 112 patients with B. pertussis infections (P = .001). Symptoms were similar among B. holmesii- and B. pertussis-infected patients. Adolescent pertussis (Tdap) booster vaccinations were more effective against B. pertussis than B. holmesii (effectiveness: 67% and 36%, respectively; 95% confidence intervals, 38%-82% and -33% to 69%, respectively).nnnCONCLUSIONSnWe report the first documented mixed outbreak of B. pertussis and B. holmesii infections. Bordetella holmesii particularly affected adolescents. Although laboratory capacity limitations might inhibit routine use of multitarget PCR for clinical diagnosis, focused testing and enhanced surveillance might improve understanding the burden of B. holmesii infection.

Malassezia furfur skin colonization of infants hospitalized in intensive care units

We studied the prevalence of Malassezia furfur skin colonization of infants hospitalized in our neonatal and infant cardiac and surgical intensive care units by culturing at monthly intervals. Of 361 infants studied over 1 year, 133 (36.8%) had at least one positive culture for M. furfur. Colonized infants, compared with noncolonized infants, had younger mean gestational age (32.4 vs 35.2 weeks, P less than 0.01), lower mean birth weight (1.76 vs 2.31 kg, P less than 0.01), a longer stay in hospital (Wilcoxon P less than 0.01), and more mean days use of an incubator (12.7 vs 7.6 days, P less than 0.01), lamb wool (12.9 vs 8.2 days, P less than 0.01), paper tape (10.8 vs 8.2 days, P less than 0.01), and Op-Site tape (14.1 vs 10.1 days, P less than 0.01). These data suggest that hospitalization in an infant intensive care unit often leads to M. furfur colonization. Although frequent adult handling may be a source, other aspects of intensive care will require careful scrutiny to define more completely the risk factors leading to M. furfur colonization of ill infants.

Pneumococcal Serotypes Causing Pneumonia with Pleural Effusion in Pediatric Patients

ABSTRACT To determine the prevalence of serotypes of Streptococcus pneumoniae responsible for pneumonia with pleural effusion, we determined the capsular polysaccharide (PS) type directly on 49 pleural fluid specimens collected from pediatric patients during 2007 to 2009 with laboratory-confirmed pneumococcal pneumonia by using monoclonal antibodies and a multiplex, bead array immunoassay. Because the fluids had to be heated to remove nonspecific reactivity before being tested in the immunoassay and type 19A PS is heat labile, the pleural fluid samples were also tested for serotype 19A capsule gene locus by PCR. Use of the multiplex immunoassay combined with type-specific 19A PCR allowed for serotype determination on 40 of 49 pleural fluids. Pneumococcal pneumonia with pleural effusion was associated with a limited number of serotypes, with types 1, 3, 7F/A, and 19A accounting for 75% of the typeable cases. The concentration of capsular PS in the pleural fluids was often greater than 1 μg/ml and sufficient to inhibit the opsonic capacity of sera from individuals who had received the 23-valent pneumococcal PS vaccine. Based on the serotypes observed before and after introduction of the 7-valent pneumococcal conjugate vaccine, the recently licensed 13-valent pneumococcal conjugate vaccine may reduce the incidence of pneumonia with pleural effusions.

Comparison of Polyurethane Foam to Nylon Flocked Swabs for Collection of Secretions from the Anterior Nares in Performance of a Rapid Influenza Virus Antigen Test in a Pediatric Emergency Department

ABSTRACT Rapid antigen testing of upper respiratory secretions collected with various swab types is often utilized for laboratory diagnoses of influenza virus infection. There are limited data on the effects of swab composition on test performance. This study compared the performance of the Quidel QuickVue Influenza A+B test on secretions from the anterior nares when a polyurethane foam swab was used for collection to that when a nylon flocked swab was used for collection. One hundred subjects who presented to a pediatric emergency department with symptoms suggestive of an influenza virus infection were recruited for the study. Foam and flocked swabs of the anterior nares were obtained from separate nares of each subject before a posterior nasopharyngeal swab was collected and placed into viral transport medium. The QuickVue test was performed directly on each swab type, and the results were compared to the results of reverse transcription-PCR (RT-PCR), direct fluorescent antibody (DFA) test, and viral culture performed on the transport medium. RT-PCR alone and DFA combined with culture were utilized as separate gold standards. There were 56 cases of influenza detected by RT-PCR; the QuickVue test was positive for 40 foam and 30 flocked swabs, for sensitivities of 71% and 54%, respectively (P = 0.01). Similarly, there were 49 influenza cases detected by DFA and/or culture; the QuickVue test was positive for 38 foam and 30 flocked swabs, for sensitivities of 78% and 61%, respectively (P = 0.13). This study suggests that polyurethane foam swabs perform better than nylon flocked swabs for the collection of secretions from anterior nares in the Quidel QuickVue Influenza A+B test.

Nasopharyngeal bacterial burden and antibiotics: Influence on inflammatory markers and disease severity in infants with respiratory syncytial virus bronchiolitis

OBJECTIVESnAnimal studies suggest that RSV increases nasopharyngeal (NP) bacterial colonization facilitating bacterial infections. We investigated the influence of antibiotic treatment and colonization with potentially pathogenic bacteria on inflammatory markers and disease severity in RSV-infected in infants.nnnMETHODSnHealthy young infants hospitalized with RSV bronchiolitis (nxa0=xa0136) and age-matched healthy controls (nxa0=xa023) were enrolled and NP samples cultured for potentially pathogenic bacteria including: Gram-positive bacteria (GPB): Staphylococcus aureus, Streptococcus pneumoniae, β-hemolytic Streptococcus; and Gram-negative bacteria (GNB): Moraxella catarrhalis and Haemophilus influenzae. Clinical parameters and plasma IL-8, IL-6 and TNF-α concentrations were compared according to the bacterial class and antibiotic treatment.nnnRESULTSnAntibiotic treatment decreased by 10-fold NP bacterial recovery. Eighty-one percent of RSV infants who did not receive antibiotics before sample collection were colonized with pathogenic bacteria. Overall, GNB were identified in 21% of patients versus 4% of controls who were mostly colonized with GPB. Additionally, in RSV patients NP white blood cell counts (pxa0=xa00.026), and blood neutrophils (pxa0=xa00.02) were higher in those colonized with potentially pathogenic bacteria versus respiratory flora. RSV patients colonized with GNB had higher plasma IL-8 (pxa0=xa00.01) and IL-6 (pxa0<xa00.01) concentrations than controls, and required longer duration of oxygen (pxa0=xa00.049).nnnCONCLUSIONSnInfants with RSV bronchiolitis colonized with potentially pathogenic bacteria had increased numbers of mucosal and systemic inflammatory cells. Specifically, colonization with GNB was associated with higher concentrations of proinflammatory cytokines and a trend towards increased disease severity.

Comparison of three major antigen detection methods for the diagnosis of Group B streptococcal sepsis in neonates.

Because of the difficulty encountered in diagnosing early onset Group B streptococcal disease (GBS) in neonates and because of the proliferation of tests to detect the antigen in urine, we made qualitative and quantitative comparisons among the three major, commercially available, antigen detection systems. The methods compared were Wellcogen latex agglutination, Phadebact coagglutination, and counterimmunoelectrophoresis (CIE). We tested urine, with or without serum, and tracheal or gastric aspirates from 176 neonates admitted to Columbus Childrens Hospital, with suspected GBS disease. Wellcogen and Phadebact were equally sensitive indicators of neonatal GBS sepsis (100%) as compared to CIE which was only 30% sensitive. CIE, however, did not produce any false-positives (100% specificity) while Phadebact coagglutination and Wellcogen latex agglutination were approximately 98% specific. As a side bar to the main study, we also set out to determine whether tracheal or gastric aspirates would be consistent and convenient sources of antigen as compared to urine. Consequently we determined that neither aspirate is a good source of antigen as performed by our method.

A Simplified Sequence-Based Identification Scheme for Bordetella Reveals Several Putative Novel Species

ABSTRACT The differentiation of Bordetella species, particularly those causing human infection, is problematic. We found that sequence analysis of an internal fragment of nrdA allowed differentiation of the currently named Bordetella species. Analysis of 107 “Bordetella” isolates recovered almost exclusively from human respiratory tract specimens identified several putative novel species.

β-lactam susceptibility of coagulase-negative staphylococci causing catheter sepsis in pediatric patients

We evaluated standard oxacillin and methicillin disk diffusion (DD) and broth microdilution (MD)-MIC tests with and without 2% NaCl for detecting heteroresistance among 47 blood isolates of coagulase-negative staphylococci (CNS) causing catheter sepsis in pediatric patients. The 24-hr oxacillin DD test detected the greatest number (40) of apparent hetero-resistant isolates, but methicillin DD and oxacillin MD-MIC with 2% NaCl performed equally as well (38 and 37 resistant isolates, respectively). An additional 24-hr incubation did not significantly increase the number of apparent heteroresistant isolates detected by these methods. Discrepant results with the various test methods occurred most commonly among Staphylococcus epidermidis isolates with MD-MIC values near the breakpoint concentrations for interpretation of susceptible and resistant strains. For detection of heteroresistance among the CNS, we encourage use of standard oxacillin DD and MD-MIC tests but would suggest that isolates with MIC values ranging from 1-2 micrograms/ml be interpreted cautiously until clinical studies demonstrate the efficacy of treating patients with infections caused by such strains.