John R. Hamilton

Expert Opinion: What To Do When There Is Coccidioides Exposure in a Laboratory

Inadvertent exposure to Coccidioides species by laboratory staff and others as a result of a mishap is not an uncommon cause of infection in clinical microbiology laboratories. These types of infection may occur in laboratories outside the endemic areas, because the etiologic agent is unexpected in the submitted specimens and because personnel may be unfamiliar with the hazards of dealing with Coccidioides species in the laboratory. Coccidioidal infections are often difficult to treat, and outcomes can be poor. Here, we emphasize prevention and an approach to a laboratory accident that minimizes the risk of exposure to laboratory staff and staff in adjacent areas. On the basis of an artificially large exposure to arthroconidia that may occur as a result of a laboratory accident, a conservative approach of close observation and early treatment of exposed staff is discussed.

Impact of a More Restrictive Approach to Urinary Tract Imaging After Febrile Urinary Tract Infection

OBJECTIVES To determine the impact of using an algorithm requiring selective rather than routine urinary tract imaging following a first febrile urinary tract infection (UTI) on imaging use, detection of vesicoureteral reflux (VUR), prophylactic antibiotic use, and UTI recurrence within 6 months. DESIGN Retrospective review comparing outcomes during periods before algorithm use (September 1, 2006, to August 31, 2007) and after algorithm use (September 1, 2008, to August 31, 2009). The new algorithm, which adapted recommendations from the United Kingdoms National Institute for Health and Clinical Excellence 2007 guidelines, was implemented in 2008. The algorithm calls for renal ultrasonography in most cases and restricts voiding cystourethrography for use in patients with certain risk factors. SETTING County health system. PARTICIPANTS Children younger than 2 years with a first febrile UTI. INTERVENTION Selective algorithm for urinary tract imaging. MAIN OUTCOME MEASURES Urinary tract imaging use, detection of VUR, prophylactic antibiotic use, and UTI recurrence within 6 months. RESULTS After introduction of the new algorithm, voiding cystourethrography and prophylactic antibiotic use decreased markedly. Rates of UTI recurrence within 6 months and detection of grades 4 and 5 VUR did not change, but detection of grades 1 to 3 VUR decreased substantially. Patients in the prealgorithm group with grades 1 to 3 VUR who would have been missed with selective screening underwent no interventions other than successive urinary tract imaging and prophylactic antibiotic use. CONCLUSIONS By restricting urinary tract imaging after an initial febrile UTI, rates of voiding cystourethrography and prophylactic antibiotic use decreased substantially without increasing the risk of UTI recurrence within 6 months and without an apparent decrease in detection of high-grade VUR. Clinicians can be more judicious in their use of urinary tract imaging.

Prevalence of measles antibodies in adults with HIV infection: possible risk factors of measles seronegativity.

ObjectivesTo determine the prevalence of measles (rubeola) immunity in a group of HIV-1-infected adults and to examine predictors of measles seronegativity in this population. SettingCounty hospital outpatient clinic and public-health department early HIV intervention clinic. PatientsA total of 262 HIV-infected adults presenting to outpatient clinics between September 1990 and January 1991. InterventionsPatients were screened for the presence of measles immunoglobulin G antibody, as measured by an enzyme-linked immunosorbent assay (ELISA). Pertinent clinical and immunologic information was recorded. Univariate and multivariate analyses were performed to identify possible risk factors for measles seronegativity. Main outcome measureMeasles seronegativity, as defined by a lack of detectable antibody (ELISA predicted index value <1.0). ResultsThirteen (5%) patients lacked serologic evidence of immunity. Risk factors for measles seronegativity included year of birth in 1957 or later, Caucasian (non-Hispanic) race and oral hairy leukoplakia. Factors associated with progressive HIV disease (other than hairy leukoplakia) were not associated with a lack of existing immunity. ConclusionsA high prevalence (95%) of measles antibody was found in this large group of HIV-infected adults. Young, white individuals born in 1957 or later were at the greatest risk for measles seronegativity, but declining immunity due to progressive HIV infection did not appear to be associated with a lack of antibody. Self-reported histories of measles infection or immunization were not reliable predictors of measles immunity.

Ruling Out Bacteremia and Bacterial Meningitis in Infants Less Than One Month of Age: Is 48 Hours of Hospitalization Necessary?

OBJECTIVE The appropriate duration of hospitalization for infants ≤ 30 days admitted for fever or other concerns for a serious bacterial infection is an understudied area. We sought to determine the risk of a positive, pathogenic bacterial culture of blood or cerebrospinal fluid (CSF) in this population beyond 24 hours after collection. METHODS This study was a retrospective review of 1145 infants aged ≤30 days who had a blood or CSF culture from 1999 to 2010 at Santa Clara Valley Medical Center, a county health system in San Jose, California. Time to notification and the probability of a positive culture result after 24 hours were calculated. Infants were considered high risk if they had either a white blood cell count <5000 or >15 000 per µL, a band count >1500 per µL, or an abnormal urinalysis. RESULTS We identified 1876 cultures (1244 blood, 632 CSF) in 1145 infants aged ≤30 days; 901 (79%) of 1145 were hospitalized and 408 (45%) of 901 hospitalizations were for fever without source (FWS). Thirty-one (2.7%) of the 1145 infants had pathogenic cultures; 6 of 1145 infants (0.5% [95% confidence interval: 0.2-1.1]) had a time to notification >24 hours. All 6 patients had FWS (1.5% of hospitalized FWS sample) and met high-risk criteria on presentation. No low-risk patients had a time to notification >24 hours. Low-risk characteristics were found in 57% (232 of 408) of the entire hospitalized FWS population. CONCLUSIONS Low-risk infants hospitalized for FWS or other concerns for serious bacterial infection may not need hospitalization for a full 48 hours simply to rule out bacteremia and bacterial meningitis.

Halomonas johnsoniae: review of a medically underappreciated genus of growing human importance.

The growing genus Halomonas includes bacteria favoring or tolerating high-saline/halide and high-pH environments. Infections are rarely reported. A patient developed Halomonas johnsoniae (previously reported only as dialysis unit environmental contaminants) bacteremia. The medical community is alerted to the pathogenic potential of the genus, particularly in a dialysis setting.