Infectious Disease Alert Updates
March 1, 2023
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By Carol A. Kemper, MD, FIDSA
Medical Director, Infection Prevention, El Camino Hospital, Palo Alto Medical Foundation
California Firefighters at Risk for Cocci
SOURCE: Donnelly MAP, Maffei D, Sondermeyer Cooksey GL, et al. Notes from the field: Coccidioidomycosis outbreak among wildland firefighters — California, 2021. MMWR Morb Mortal Wkly Rep 2022;71:1095-1096.
In late June 2021, a lightning strike sparked an 18-acre fire in the mountains south of Tehachapi, CA. Approximately 130 firefighters from the Bureau of Land Management (BLM), Kern County, the U.S. Forest Service, and CAL FIRE were dispatched to manage the fire, which was largely contained over the next week. The Tehachapis extend for approximately 40 miles from southern Kern County to northwestern Los Angeles and form the boundary between the San Joaquin Valley and the Mojave Desert. They were the site of a devastating fire in 2010 that consumed 40 homes and caused 2,300 people to be evacuated. The area is well known to be high risk for coccidioidomycosis — and Kern County has the highest rates of cocci infection per county in California (2020 data, 285 cases/100,000 population).
Seven firefighters from Crew A (19 individuals) and Crew B (21 members) developed respiratory symptoms and were seen in various urgent care centers and emergency rooms two to three times each with shortness of breath, chest discomfort, and cough from July 17 to Aug. 4, 2021. All received negative testing for SARS-CoV-2. Three were hospitalized with laboratory confirmed coccidioidomycosis, two of them with severe illness. Testing in the other four was negative for cocci. Two received follow-up testing, which was recommended by CAL FIRE, which was negative, and two others were lost to follow-up. The three confirmed cases were men, ages 25-34 years, with no remarkable past medical history. Two reported Latino/Hispanic race or ethnicity, which increases their risk for more severe cocci infection.
These two crews worked on digging trenches and extinguishing the remains of the fire by removing brush, digging and moving soil, and cooling ash pits, which is referred to as “mopping up a fire.” None wore respiratory protection. The three confirmed cases were part of Crew B, giving an attack rate of 14.3% for that crew.
Firefighters are at particular risk for cocci infection when working in an endemic area. An outbreak of cocci was previously described in 22 youth responding to a wildfire in Kern County in 2000 (as part of the California Youth Authority). And in 2017, an outbreak of coccidioidomycosis occurred among 10 inmate firefighters responding to a California wildfire.1 Multivariate analysis showed that risk of infection was increased with moving dirt, tossing dirt in the air, and using McLeod’s ground dirt cutting tool (which is a hoe-like tool with teeth on one side and a cutting blade on the other). Many of CAL FIRE ground crews are composed of inmate firefighters.
The California Department of Public Health has recommended that California wildland fighters receive training for cocci exposure. CAL FIRE has developed policies regarding education surrounding cocci exposure risk, the use of proper respiratory equipment in high-risk areas, possible symptoms, and when to seek care. But many firefighters are reluctant to use respiratory equipment since conditions are already hot and challenging. Other recommendations include wetting soil before disturbing it to reduce dust, staying upwind while performing tasks, using heavy machinery rather than hand trenching when possible, and using dirt movers with closed cabs with air conditioning on recirculation. Proper storage and cleaning of clothing and gear is important — changing clothes and showering immediately following a workday is recommended, since dust on clothing, shoes, equipment, and even vehicles can carry cocci spores. Fire camps for personnel should be located upwind whenever possible. With the 2021 Tehachapi event, CAL FIRE did a good job of reaching out to firefighters and recommending testing, and cases were diagnosed within 10-12 days of symptom onset.
REFERENCE
- Laws RL, Jain S, Sondermeyer Cooksey G, et al. Coccidioidomycosis outbreak among inmate wildland firefighters: California, 2017. Am J Ind Med 2021;64:266-273.
Hyperglycemia and Diabetes with INSTIs
SOURCE: O’Halloran JA, Sahrmann J, Parra- Rodriguez L, et al. Integrase strand transfer inhibitors are associated with incident diabetes mellitus in people with human immunodeficiency virus. Clin Infect Dis 2022;75:2060-2065.
Integrase strand transfer inhibitor therapy (INSTI) has become increasingly common during the past 15 years, since approval of the first INSTI agent, raltegravir, by the Food and Drug Administration in October 2007. Current human immunodeficiency virus (HIV) treatment guidelines specify several INSTI agents as among the first-line agents for initial antiretroviral (ART) therapy. While INSTI agents are remarkably well-tolerated, weight gain following initiation of INSTI therapy has been one unwanted observed side effect, with approximately an average of 5 kg of weight gain in men and 10 kg of weight gain in women. Concern has been raised about other possible metabolic side effects of INSTI therapy.
Using large-scale market databases for commercially insured and Medicaid patients, these authors examined the risk of hyperglycemia and new-onset diabetes in 42,382 HIV-infected persons within six months of initiating ART treatment between 2007 and 2019. Inclusion criteria included the standard use of two to three ART agents. Patients with a history of diabetes or pre-diabetes were excluded from the analysis. Fifty-four percent of individuals received an INSTI agent (including 39.5% receiving raltegravir, 28.1% receiving elvitegravir, 26.7% receiving dolutegravir, and 5.7% receiving bictegravir). The average participant age was 38 years, 79% were male, and 19% were Medicaid participants. The presence of obesity at baseline was small for persons receiving either INSTI- or non-INSTI-containing regimens (4.9% vs. 2.2%, respectively). Two-thirds of the patients had received screening for blood sugar and/or hemoglobin A1c (HbA1c) within the six months before initiation of ART. In the six months following initiation of ART, 63% to 68% of non-INSTI users and 64% to 72% of INSTI users had blood sugar and/or HbA1c screening.
HIV-infected persons receiving INSTI therapy had a 31% increased risk of hyperglycemia and/or new-onset diabetes within six months compared with non-INSTI regimens (hazard ratio [HR], 131; 95% confidence interval [CI] 1.15-1.48; P < 0.001). This increased risk was highest for elvitegravir (HR, 1.54; CI, 1.32-1.79; P < 0.001) and dolutegravir (HR, 1.26; CI, 1.03-1.55; P = 0.027), and lowest for raltegravir (HR, 1.19; CI, 1.03-1.37; P = 0.18). Use of tenofovir alafenamide was not associated with an increased risk of hyperglycemia and/or new-onset diabetes.
This study was a retrospective, non-randomized observational study, and as such, screening for diabetes and elevated blood sugar was not systematically performed. Earlier observations were more likely to be based on blood sugar testing, while the use of HbA1c became more common in later years. Although the groups were fairly well balanced at baseline, and the presence of baseline obesity was small, the risk of weight gain and its relationship to the observed outcome in this study was not assessed.
Positive Sputum in Extra-Pulmonary Tuberculosis
SOURCE: Le V, Pascopella L, Westenhouse J, Barry P. A cross-sectional study of patients with extrapulmonary tuberculosis and normal chest radiographs – what characteristics were associated with sputum culture positivity? Clin Infect Dis 2022;75:2113-2118.
Our small group of three infectious disease specialists routinely obtains sputum smears and cultures in patients with extra-pulmonary sites of tuberculosis (EPTB) infection, even when chest radiographs are negative, and patients lack pulmonary symptoms. Despite a lack of apparent pulmonary involvement, about 10% to 14% of such patients nonetheless will have a positive culture for TB — often making this a useful test in this population. For one thing, since many of our patients with TB in Silicon Valley are foreign-born and at risk for drug-resistance, I am always hoping to have an organism in culture to perform pyrosequencing and/or susceptibility studies. Further, not anticipating TB, mycobacterial cultures are not always obtained with surgically obtained specimens, and sputum cultures may be your only shot at obtaining confirmation of TB infection and susceptibility testing.
Using the California TB Registry, these authors assessed the frequency and characteristics of patients > 15 years of age with EPTB from 2011-2017. Of the 15,045 persons with TB reported to the California Department of Public Health during this period, 4,278 (30%) had sites of EPTB involvement. A total of 1,151 (27%) of these had pleural, intrathoracic, or laryngeal involvement and were excluded from the analysis. Of the remaining patients with EPTB and a normal chest radiograph, sputum was obtained for culture in 937 (57%) and no sputum was obtained in 689 (43%). Virtually all of the patients with sputum for culture also had acid fast sputum smears done, but only a minority (14%) had nucleic acid amplification testing (NAAT).
Of these 937 persons with EPTB, a normal chest radiograph and sputum, 13.5% had a positive culture. Most of these (85%) were non-bovis strains, whereas 13% had Mycobacterium bovis identified in culture. Baseline clinical characteristics were similar between those with positive vs. negative sputum culture with one exception: Patients with EPTB and human immunodeficiency virus (HIV) co-infection were much more likely to have a positive sputum culture (54%) compared to those without HIV infection (9.5%). In addition, patients with a positive sputum culture were much more likely to have two or more sites of EPTB involvement (15%) compared to those with negative cultures (5%).
Interestingly, sites of EPTB involvement were similar between those with a positive vs. negative sputum culture. Sites of EPTB involvement in those with a positive sputum culture included lymph nodes (50%), bone/joint (18%), peritoneal (12%), gastrointestinal (12%), central nervous system (CNS) (11%), and genitourinary (9%). In contrast, sites of EPTB involvement in those with a negative sputum culture included lymph nodes (49%), bone/joint (11%), peritoneal (8%), gastrointestinal (8%), CNS (8%), and genitourinary (8%). Of the 36 patients with EPTB and a positive sputum culture, and who also had NAAT testing, 61% had a positive NAAT result and 39% had negative NAAT. Interestingly, of the 63 patients with EPTB and a positive sputum culture who also had computed tomography (CT), 92% had an abnormal CT and 8% had a normal CT, suggesting many of these patients had early or occult pulmonary TB.
In conclusion, a little more than half of those with EPTB and a negative chest X-ray had sputum cultures performed, and 13.5% of these were positive for TB. Only a minority had NAAT testing performed, although the Centers for Disease Control and Prevention recommends that NAAT testing be performed on at least one respiratory specimen for each patient “for whom a diagnosis of TB is being considered but not yet established.” Detection of patients with occult pulmonary involvement can both confirm the diagnosis and allow for increasingly important susceptibility testing — and may be useful in identifying patients at risk for transmission. CT scanning revealed abnormalities in the majority of these patients. The number of sputum cultures obtained per person was not available, nor was there information on how those specimens were obtained. Generally, obtaining three separate sputum specimens is ideal, at least one of which is an early morning specimen, and induced specimens, when available, may provide greater yield.
California Firefighters at Risk for Cocci; Hyperglycemia and Diabetes with INSTIs; Positive Sputum in Extra-Pulmonary Tuberculosis
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