Public Health Response to Multistate Salmonella Typhimurium Outbreak Associated with Prepackaged Chicken Salad, United States, 2018.

Quantifying the effect of public health actions on population health is essential when justifying sustained public health investment. Using modeling, we conservatively estimated that rapid response to a multistate foodborne outbreak of Salmonella Typhimurium in the United States in 2018 potentially averted 94 reported cases and $633,181 in medical costs and productivity losses.

Cost of Public Health Response and Outbreak Control With a Third Dose of Measles-Mumps-Rubella Vaccine During a University Mumps Outbreak-Iowa, 2015-2016.

BACKGROUND: The United States is experiencing mumps outbreaks in settings with high 2-dose measles-mumps-rubella (MMR) vaccine coverage, mainly universities. The economic impact of mumps outbreaks on public health systems is largely unknown. During a 2015-2016 mumps outbreak at the University of Iowa, we estimated the cost of public health response that included a third dose of MMR vaccine. METHODS: Data on activities performed, personnel hours spent, MMR vaccine doses administered, miles traveled, hourly earnings, and unitary costs were collected using a customized data tool. These data were then used to calculate associated costs. RESULTS: Approximately 6300 hours of personnel time were required from state and local public health institutions and the university, including for vaccination and laboratory work. Among activities demanding time were case/contact investigation (36%), response planning/coordination (20%), and specimen testing and report preparation (13% each). A total of 4736 MMR doses were administered and 1920 miles traveled. The total cost was >$649 000, roughly equally distributed between standard outbreak control activities and third-dose MMR vaccination (55% and 45%, respectively). CONCLUSIONS: Public health response to the mumps outbreak at the University of Iowa required important amounts of personnel time and other resources. Associated costs were sizable enough to affect other public health activities.

Evaluation of potential environmental contamination sources for the presence of multidrug-resistant bacteria linked to wound infections in combat casualties.

OBJECTIVE: To determine whether multidrug-resistant (MDR) gram-negative organisms are present in Afghanistan or Iraq soil samples, contaminate standard deployed hospital or modular operating rooms (ORs), or aerosolize during surgical procedures. DESIGN: Active surveillance. SETTING: US military hospitals in the United States, Afghanistan, and Iraq. METHODS: Soil samples were collected from sites throughout Afghanistan and Iraq and analyzed for presence of MDR bacteria. Environmental sampling of selected newly established modular and deployed OR high-touch surfaces and equipment was performed to determine the presence of bacterial contamination. Gram-negative bacteria aerosolization during OR surgical procedures was determined by microbiological analysis of settle plate growth. RESULTS: Subsurface soil sample isolates recovered in Afghanistan and Iraq included various pansusceptible members of Enterobacteriaceae, Vibrio species, Pseudomonas species, Acinetobacter lwoffii, and coagulase-negative Staphylococcus (CNS). OR contamination studies in Afghanistan revealed 1 surface with a Micrococcus luteus. Newly established US-based modular ORs and the colocated fixed-facility ORs revealed no gram-negative bacterial contamination prior to the opening of the modular OR and 5 weeks later. Bacterial aerosolization during surgery in a deployed fixed hospital revealed a mean gram-negative bacteria colony count of 12.8 colony-forming units (CFU)/dm(2)/h (standard deviation [SD], 17.0) during surgeries and 6.5 CFU/dm(2)/h (SD, 7.5; [Formula: see text]) when the OR was not in use. CONCLUSION: This study demonstrates no significant gram-negative bacilli colonization of modular and fixed-facility ORs or dirt and no significant aerosolization of these bacilli during surgical procedures. These results lend additional support to the role of nosocomial transmission of MDR pathogens or the colonization of the patient themselves prior to injury.

Improving detection of extended-spectrum beta-lactamase-producing bacteria in a deployed setting.

INTRODUCTION: Organisms that produce extended-spectrum beta-lactamase (ESBL) are significant causes of infection among deployed service members. These specific organisms have increased resistance to several antibiotics, limiting the choice of therapy for the provider. Currently, the deployed microbiology lab uses, by default, the Siemens NBPC30 panel to identify and measure antibiotic susceptibility of gram-negative organisms. However, when an ESBL is suspected, additional confirmatory testing is performed, during which time the health care provider is forced to use broad spectrum antibiotics to protect the patient from infection. In this study, we evaluated the NBPC30 and NBC41 panels for their ability to rapidly and accurately detect ESBL-producing organisms. METHODS: Identification and antimicrobial susceptibility testing of 79 strains of Enterobacteriaceae isolated from patients treated at Ibn Sina tertiary hospital (Baghdad) were performed using the NBPC30 and NBC41 panels. These results were confirmed using a Kirby-Bauer disk diffusion reference method described by the Clinical Laboratory Standards Institute. Sensitivities and specificities of the panels were determined in relation to this reference method. RESULTS: Sensitivity and specificity of the NBC41 were 96.7% and 89%, while they were 86.7% and 72% for the NBPC30 panel. False positive and false negative rates were higher for the NBPC30 panel. CONCLUSION: Our data shows that the NBC41 panel is superior to the NBPC30 panel in rapidly identifying ESBL-producing organisms. Use of the NBPC41 panel decreases the turnaround time by 24 hours, allowing the provider to more accurately apply appropriate antibiotic therapy. Additionally, the NBPC41 panel provides more useful antibiotic susceptibility results compared to the NBPC30. We recommend use of this panel as a primary identification and susceptibility panel for gram-negative organisms.

Rates of gonorrhea and Chlamydia in U.S. military personnel deployed to Iraq and Afghanistan (2004-2009).

The increased incidence of sexually transmitted infections has historically been associated with military personnel at war. The incidence of gonorrhea and Chlamydia in personnel deployed in the current wars in Iraq and Afghanistan has not been reported. An electronic records' review of testing done from January 2004 to September 2009 revealed higher rates of Chlamydia than gonorrhea, especially among females who deploy to Iraq. Additionally, increasing Chlamydia rates were noted over the study. Overall, the rates of gonorrhea and Chlamydia were the same or lower than age- and year-matched U.S. rates reported by the Center for Disease Control and Prevention. Ongoing education with emphasis on prevention and treatment are needed, as are development of specific projects to define the risk factors and timing of acquisition of sexually transmitted infections in combat zones.

Prevalence of methicillin-resistant staphylococcus aureus in a combat support hospital in Iraq.

Methicillin-resistant Staphylococcus aureus (MRSA) in health-care settings results in life-threatening infections. We examined the incidence of MRSA at the combat support hospital located at the Ibn Sina Hospital in Baghdad, Iraq. We compiled isolate data from 2005 to 2009 characterizing antibiotic susceptibilities, annual trends, patient populations, infection sites, and hospital locations. Approximately 46.1% of S. aureus were MRSA, with increase in numbers of yearly isolates. MRSA was isolated in higher numbers from U.S. military personnel. Non-U.S. patient isolates displayed higher antibiotic susceptibility compared to U.S. military personnel isolates. Outpatient clinic, forward operating bases, and intermediate care ward 1 isolated the most MRSA. Common isolation sites were wound and skin cultures. Community-acquired MRSA was likely present in 291 out of 303 isolates based on antibiotic susceptibility. Our data suggests that most MRSA were community-acquired with limited nosocomial spread. We recommend increases in combat support hospital molecular lab capability to rapidly identify both MRSA categories.

Changes in the incidences of multidrug-resistant and extensively drug-resistant organisms isolated in a military medical center.

BACKGROUND: Multidrug-resistant (MDR) Acinetobacter baumannii and Pseudomonas aeruginosa have emerged as the causes of nosocomial infections in critically ill patients. OBJECTIVE: To characterize the incidence of these MDR bacteria over time in the military healthcare system, comparing isolates recovered from overseas combat casualties with isolates recovered from local military and civilian patients. METHODS: Retrospective electronic records review of culture and/or susceptibility testing results of patients admitted to a military level I trauma center in San Antonio, Texas, during the period from January 2001 through December 2008. Multidrug resistance was defined as the first isolated organism resistant to 3 or more classes of antimicrobial agents. RESULTS: Over time, the percentage of MDR A. baumannii isolates increased from 4% to 55%, whereas the percentage of MDR P. aeruginosa isolates increased from 2% to 8%. Respiratory tract specimens had a higher percentage of MDR A. baumannii isolates (49%), compared with specimens obtained from blood (30%), wound sites (24%), or urine (19%). No difference in the percentages of MDR P. aeruginosa isolates was observed with regard to source of specimen. The percentage of MDR A. baumannii isolates recovered was higher among patients who had been deployed overseas (52%) than among local patients (20%). When isolates recovered from patients in the burn intensive care unit (53% of MDR A. baumannii isolates) were removed from analysis, the percentage of MDR A. baumannii isolates decreased from 38% to 30% while the percentage of MDR P. aeruginosa isolates remained unaffected. CONCLUSION: The percentage of MDR A. baumannii isolates increased in this facility among combat casualties and among local patients, which indicates nosocomial transmission; however, there was no significant increase in the percentage of MDR P. aeruginosa isolates. Isolated changes in the MDR pathogens within a facility can occur. Possible interventions to limit the spread of these organisms could include implementing aggressive infection control practices, controlling antibiotic use, and using active culture surveillance.

Incidence and bacteriology of burn infections at a military burn center.

Considerable advancements in shock resuscitation and wound management have extended the survival of burned patients, increasing the risk of serious infection. We performed a 6-year review of bacteria identification and antibiotic susceptibility records at the US Army Institute of Surgical Research Burn Center between January 2003 and December 2008. The primary goal was to identify the bacteria recovered from patients with severe burns and determine how the bacteriology changes during extended hospitalization as influenced by population and burn severity. A total of 460 patients were admitted to the burn ICU with 3507 bacteria recovered from 13,727 bacteriology cultures performed. The most prevalent organisms recovered were Acinetobacter baumannii (780), Pseudomonas aeruginosa (703), Klebsiella pneumoniae (695) and Staphylococcus aureus (469). A. baumannii was most often recovered from combat-injured (58%) and S. aureus the most frequent isolate from local (46%) burn patients. Culture recovery rate of A. baumannii and S. aureus was highest during the first 15 hospital days (73% and 71%); while a majority of P. aeruginosa and K. pneumoniae were recovered after day 15 (63% and 53%). All 4 pathogens were recovered throughout the course of hospitalization. A. baumannii was the most prevalent pathogen recovered from patients with total body surface area (TBSA) burns less than 30% (203) and 30-60% (338) while P. aeruginosa was most prevalent in patients with burns greater than 60% TBSA (292). Shifting epidemiology of bacteria recovered during extended hospitalization, bacteriology differences between combat-injured and local burn patients, and impact of % TBSA may affect patient management decisions during the course of therapy.

Prevalence of multidrug-resistant organisms recovered at a military burn center.

Infections caused by multidrug-resistant (MDR) pathogens are associated with significant morbidity and mortality in patients with burn injuries. We performed a 6-year antibiotic susceptibility records review from January 2003 to December 2008 to assess the prevalence of MDR isolates by pathogen at the US Army Institute of Surgical Research Burn Center. During the study period Acinetobacter baumannii (780 isolates [22%]) was the most prevalent organism recovered, followed by Pseudomonas aeruginosa (703 isolates [20%]), Klebsiella pneumoniae (695 isolates [20%]), and Staphylococcus aureus (469 isolates [13%]). MDR prevalence rates among these isolates were A. baumannii 53%, methicillin-resistant S. aureus (MRSA) 34%, K. pneumoniae 17% and P. aeruginosa 15%. Two isolates, 1 A. baumannii and 1 P. aeruginosa, were identified as resistant to all 4 classes of antibiotics tested plus colistin. A. baumannii isolates recovered from patients with burns greater than 30% of total body surface area (TBSA) were more likely to be MDR (61%) with no significant difference for P. aeruginosa and K. pneumoniae. A higher proportion of MDR P. aeruginosa isolates were recovered from respiratory specimens compared to blood specimens (24% vs. 9%) while the opposite was true for MRSA (35% vs. 54%). A comparison of A. baumannii recovered during hospitalization days 1-5 and 15-30 revealed higher MDR levels as length of stay increased (48% vs. 75%) while no significant trends were observed for P. aeruginosa and K. pneumoniae. A similar pattern was observed for MDR A. baumannii levels for the facility between 2003 and 2005 and 2006-2008 (39% vs. 70%), with no significant increase in MDR P. aeruginosa and MDR K. pneumoniae. Increasing antibiotic resistance patterns of the most prevalent isolates recovered during extended hospitalization, impact of % TBSA and other clinical parameters may affect empirical antimicrobial therapy and patient management decisions during treatment.

Recovery of multidrug-resistant bacteria from combat personnel evacuated from Iraq and Afghanistan at a single military treatment facility.

U.S. combat casualties from Iraq and Afghanistan continue to develop infections with multidrug-resistant (MDR) bacteria. This study assesses the infection control database and clinical microbiology antibiograms at a single site from 2005 to 2007, a period when all Operation Iraqi Freedom (OIF)/Operation Enduring Freedom (OEF) casualties admitted to the facility underwent initial isolation and screening for MDR pathogens. During this 3-year period, there were 2,242 OIF/OEF admissions: 560 in 2005, 724 in 2006, and 958 in 2007. The most commonly recovered pathogens from OIF/OEF admission screening cultures were methicillin-resistant Staphylococcus aureus (MRSA), Klebsiella pneumoniae and Acinetobacter. The yearly nosocomial infection rate of these three pathogens among OIF/OEF admissions ranged between 2 and 4%. There were remarkable changes in resistance profiles for Acinetobacter, K. pneumoniae, and S. aureus over time. Despite aggressive infection control procedures, there is continued nosocomial transmission within the facility and increasing antimicrobial resistance in some pathogens. Novel techniques are needed to control the impact of MDR bacteria in medical facilities.

Description and validation of a novel real-time RT-PCR enterovirus assay.

BACKGROUND: Enteroviruses are a leading cause of aseptic meningitis in adult and pediatric populations. We describe the development of a real-time RT-PCR assay that amplifies a small target in the 5' nontranslated region upstream of the classical Rotbart enterovirus amplicon. The assay includes an RNA internal control and incorporates modified nucleotide chemistry. METHODS: We evaluated the performance characteristics of this design and performed blinded parallel testing on clinical samples, comparing the results with a commercially available RT-PCR assay (Pan-Enterovirus OligoDetect kit) that uses an enzyme immunoassay-like plate end detection. RESULTS: We tested 778 samples and found 14 discrepant samples between the 2 assays. Of these, the real-time assay detected 6 samples that were negative by the OligoDetect kit, 5 of which were confirmed as positive by sequence analysis using an alternative primer set. Eight discrepant samples were positive by the OligoDetect kit and real-time negative, with 6 confirmed by sequencing. Overall, detection rates of 97% and 96% were obtained for the OligoDetect kit and real-time assays, respectively. Sequence analysis revealed the presence of a number of single nucleotide polymorphisms in the targeted region. The comparative sensitivities of the 2 assays were equivalent, with the limit of detection for the real-time assay determined to be approximately 430 copies per milliliter in cerebrospinal fluid. CONCLUSIONS: This novel real-time enterovirus assay is a sensitive and suitable assay for routine clinical testing. The presence of single nucleotide polymorphisms can affect real-time PCR assays.

Comparison of real-time polymerase chain reaction using the Smart Cycler and the Gen-Probe amplified Mycobacterium tuberculosis direct test for detection of M. tuberculosis complex in clinical specimens.

The performance of a real-time polymerase chain reaction (PCR) assay using the Smart Cycler instrument and a minor groove binding MGB Eclipse probe (Epoch Biosciences, Bothell, WA) for identification of Mycobacterium tuberculosis complex in acid-fast bacillus smear-positive and smear-negative clinical specimens was assessed by comparing results to the Amplified M. tuberculosis Direct Test (MTD) and mycobacterial culture plus clinical diagnosis. After initial testing, the overall sensitivity, specificity, and positive and negative predictive values of PCR for the 172 specimens submitted for mycobacterial culture were 86.3%, 100%, 100%, and 94.5%, respectively. These same values for MTD were 98.0%, 99.2%, 98.0%, and 99.2%. For 83 additional specimens, only MTD and PCR were performed; 5 specimens were positive and 78 were negative by both tests. The sensitivity of the PCR assay was improved by using different primers and probes. The time to a result for real-time PCR, starting with a decontaminated sample, was less than 3 h compared with 5-6 h for the MTD.

Comparison of six methods of extracting Mycobacterium tuberculosis DNA from processed sputum for testing by quantitative real-time PCR.

Six methods of extracting Mycobacterium tuberculosis DNA from sputum for testing by quantitative PCR were compared: Tris-EDTA (TE) buffer, PrepMan Ultra, 2% sodium dodecyl sulfate (SDS)-10% Triton X with and without sonication, Infectio Diagnostics, Inc. (IDI) lysing tubes, and QIAGEN QIAamp DNA mini kit; all included a 15-min boiling step. Pooled digested and decontaminated sputum was spiked with M. tuberculosis ATCC 27294. Each extraction method was repeated eight times. Quantitative PCR was performed on the Smart Cycler and Rotor-Gene 3000 using primers targeting an 83-bp fragment of IS6110. An minor grove binding Eclipse probe with a fluorescent label was used for detection. An internal control was included to detect amplification inhibition. The limit of detection of M. tuberculosis DNA was 0.5 fg with both instruments. Calculated DNA concentrations (picograms) extracted using IDI, PrepMan, QIAGEN, and TE were 42.8, 30.4, 28.2, and 7.4, respectively, when run on the Smart Cycler, and 51.7, 20.1, 14.9, and 8.6, respectively, when run on Rotor-Gene. All extractions using SDS/Triton X with or without sonication were inhibited. Of the extraction methods evaluated, IDI lysis tubes provided the greatest yield of mycobacterial DNA, and the procedure can be completed in less than 1 h versus 2.5-3 h for the QIAGEN extraction.

A comparison of Thermo Electron RSV OIA to viral culture and direct fluorescent assay testing for respiratory syncytial virus.

BACKGROUND: Rapid diagnostic methods for respiratory syncytial virus are useful tools available for the clinician. OBJECTIVES: The Thermo Electron RSV OIA (optical immunoassay kit) was prospectively compared with direct immunofluorescent assay and viral culture at Primary Children's Medical Center, Salt Lake City, Utah. STUDY DESIGN: Specimens from three hundred and thirty patients exhibiting respiratory symptoms were collected for testing by the three methods above. Several specimens were positive by both OIA and DFA with a negative culture result. These culture results were verified by RT-PCR analysis. RESULTS: Overall, 107 specimens were positive for RSV by the reference tests (culture or RT-PCR). DFA analysis identified an additional 40 patient specimens positive for other respiratory viruses. Compared to the reference tests the sensitivity, specificity, positive, and negative predictive values of the OIA for detection of RSV were 87.9%, 99.6%, 98.9% and 94.5%, respectively. CONCLUSIONS: The rapid OIA assay format proved to be cost effective, and simple to use in comparison to DFA and viral culture. Negative rapid test results should still be confirmed with a secondary test.

A comparison of Binax NOW to viral culture and direct fluorescent assay testing for respiratory syncytial virus.

The Binax NOW immunochromatographic assay for respiratory syncytial virus was prospectively compared with direct fluorescent assay and viral culture at Primary Children's Medical Center, Salt Lake City, Utah during February 2003. Three hundred ten patient specimens were collected for testing, of which 102 specimens were positive for respiratory syncytial virus by the reference tests, direct immunofluorescence assay (DFA), and culture or molecular analysis. DFA analysis identified an additional 40 patient specimens positive for other respiratory viruses. Compared to the reference tests, the sensitivity, specificity, and positive and negative predictive values of the rapid immunochromatographic assay for detection of respiratory syncytial virus were 89.2%, 100.0%, 100.0%, and 94.9%, respectively. This rapid assay format proved to be cost-effective and simple to use in comparison to DFA and viral culture. Negative rapid test results should still be confirmed with a secondary test.