Respiratory Illness Caused by Corynebacterium diphtheriae and C. ulcerans, and Use of Diphtheria Antitoxin in the United States, 1996-2018.

BACKGROUND: Respiratory diphtheria is a toxin-mediated disease caused by Corynebacterium diphtheriae. Diphtheria-like illness, clinically indistinguishable from diphtheria, is caused by Corynebacterium ulcerans, a zoonotic bacterium that can also produce diphtheria toxin. In the United States, respiratory diphtheria is nationally notifiable: specimens from suspected cases are submitted to the Centers for Disease Control and Prevention (CDC) for species and toxin confirmation, and diphtheria antitoxin (DAT) is obtained from CDC for treatment. We summarize the epidemiology of respiratory diphtheria and diphtheria-like illness and describe DAT use during 1996-2018 in the United States. METHODS: We described respiratory diphtheria cases reported to the National Notifiable Diseases Surveillance System (NNDSS) and C. ulcerans-related diphtheria-like illness identified through specimen submissions to CDC during 1996-2018. We reviewed DAT requests from 1997 to 2018. RESULTS: From 1996 to 2018, 14 respiratory diphtheria cases were reported to NNDSS. Among these 14 cases, 1 was toxigenic and 3 were nontoxigenic C. diphtheriae by culture and Elek, 6 were culture-negative but polymerase chain reaction (PCR)-positive for diphtheria toxin gene, 1 was culture-positive without further testing, and the remaining 3 were either not tested or tested negative. Five cases of respiratory diphtheria-like illness caused by toxigenic C. ulcerans were identified. DAT was requested by healthcare providers for 151 suspected diphtheria cases between 1997 and 2018, with an average of 11 requests per year from 1997 to 2007, and 3 per year from 2008 to 2018. CONCLUSIONS: Respiratory diphtheria remains rare in the United States, and requests for DAT have declined. Incidental identification of C. ulcerans-related diphtheria-like illness suggests surveillance of this condition might be warranted.

Investigation of a Large Diphtheria Outbreak and Cocirculation of Corynebacterium pseudodiphtheriticum Among Forcibly Displaced Myanmar Nationals, 2017-2019.

BACKGROUND: Diphtheria, a life-threatening respiratory disease, is caused mainly by toxin-producing strains of Corynebacterium diphtheriae, while nontoxigenic corynebacteria (eg, Corynebacterium pseudodiphtheriticum) rarely causes diphtheria-like illness. Recently, global diphtheria outbreaks have resulted from breakdown of health care infrastructures, particularly in countries experiencing political conflict. This report summarizes a laboratory and epidemiological investigation of a diphtheria outbreak among forcibly displaced Myanmar nationals in Bangladesh. METHODS: Specimens and clinical information were collected from patients presenting at diphtheria treatment centers. Swabs were tested for toxin gene (tox)-bearing C. diphtheriae by real-time polymerase chain reaction (RT-PCR) and culture. The isolation of another Corynebacterium species prompted further laboratory investigation. RESULTS: Among 382 patients, 153 (40%) tested tox positive for C. diphtheriae by RT-PCR; 31 (20%) PCR-positive swabs were culture confirmed. RT-PCR revealed 78% (298/382) of patients tested positive for C. pseudodiphtheriticum. Of patients positive for only C. diphtheriae, 63% (17/27) had severe disease compared to 55% (69/126) positive for both Corynebacterium species, and 38% (66/172) for only C. pseudodiphtheriticum. CONCLUSIONS: We report confirmation of a diphtheria outbreak and identification of a cocirculating Corynebacterium species. The high proportion of C. pseudodiphtheriticum codetection may explain why many suspected patients testing negative for C. diphtheriae presented with diphtheria-like symptoms.

Recent Increase in COVID-19 Cases Reported Among Adults Aged 18-22 Years - United States, May 31-September 5, 2020.

Although children and young adults are reportedly at lower risk for severe disease and death from infection with SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), than are persons in other age groups (1), younger persons can experience infection and subsequently transmit infection to those at higher risk for severe illness (2-4). Although at lower risk for severe disease, some young adults experience serious illness, and asymptomatic or mild cases can result in sequelae such as myocardial inflammation (5). In the United States, approximately 45% of persons aged 18-22 years were enrolled in colleges and universities in 2019 (6). As these institutions reopen, opportunities for infection increase; therefore, mitigation efforts and monitoring reports of COVID-19 cases among young adults are important. During August 2-September 5, weekly incidence of COVID-19 among persons aged 18-22 years rose by 55.1% nationally; across U.S. Census regions,* increases were greatest in the Northeast, where incidence increased 144.0%, and Midwest, where incidence increased 123.4%. During the same period, changes in testing volume for SARS-CoV-2 in this age group ranged from a 6.2% decline in the West to a 170.6% increase in the Northeast. In addition, the proportion of cases in this age group among non-Hispanic White (White) persons increased from 33.8% to 77.3% during May 31-September 5. Mitigation and preventive measures targeted to young adults can likely reduce SARS-CoV-2 transmission among their contacts and communities. As colleges and universities resume operations, taking steps to prevent the spread of COVID-19 among young adults is critical (7).

Global Epidemiology of Diphtheria, 2000-20171.

In 2017, a total of 8,819 cases of diphtheria were reported worldwide, the most since 2004. However, recent diphtheria epidemiology has not been well described. We analyzed incidence data and data from the literature to describe diphtheria epidemiology. World Health Organization surveillance data were 81% complete; completeness varied by region, indicating underreporting. As national diphtheria-tetanus-pertussis (DTP) 3 coverage increased, the proportion of case-patients <15 years of age decreased, indicating increased protection of young children. In countries with higher case counts, 66% of case-patients were unvaccinated and 63% were <15 years of age. In countries with sporadic cases, 32% of case-patients were unvaccinated and 66% were >15 years of age, consistent with waning vaccine immunity. Global DTP3 coverage is suboptimal. Attaining high DTP3 coverage and implementing recommended booster doses are necessary to decrease diphtheria incidence. Collection and use of data on subnational and booster dose coverage, enhanced laboratory capacity, and case-based surveillance would improve data quality.

Prevention of Pertussis, Tetanus, and Diphtheria with Vaccines in the United States: Recommendations of the Advisory Committee on Immunization Practices (ACIP).

This report compiles and summarizes all recommendations from CDC's Advisory Committee on Immunization Practices (ACIP) regarding prevention and control of tetanus, diphtheria, and pertussis in the United States. As a comprehensive summary of previously published recommendations, this report does not contain any new recommendations and replaces all previously published reports and policy notes; it is intended for use by clinicians and public health providers as a resource. ACIP recommends routine vaccination for tetanus, diphtheria, and pertussis. Infants and young children are recommended to receive a 5-dose series of diphtheria and tetanus toxoids and acellular pertussis (DTaP) vaccines, with one adolescent booster dose of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine. Adults who have never received Tdap also are recommended to receive a booster dose of Tdap. Women are recommended to receive a dose of Tdap during each pregnancy, which should be administered from 27 through 36 weeks' gestation, regardless of previous receipt of Tdap. After receipt of Tdap, adolescents and adults are recommended to receive a booster tetanus and diphtheria toxoids (Td) vaccine every 10 years to assure ongoing protection against tetanus and diphtheria.

Characterization of serum anti-diphtheria antibody activity following administration of equine anti-toxin for suspected diphtheria.

There is a global shortage of equine-derived diphtheria anti-toxin (DAT) for diphtheria treatment. There are few existing data on serum antibody concentrations and neutralizing activity post-treatment to support development of new therapeutics. Antibody concentrations were quantified by ELISA and anti-toxin neutralizing activity by cytotoxicity assay in serum from 4 patients receiving DAT for suspected diphtheria. Using linear mixed effects modeling, estimated mean (SE) half-life was 78.2 (20.0) hours. Maximum serum neutralizing activity ranged from 28.42-38.64 AU/mL with an estimated mean AUC1-72 of 1396.7 (399.3) AU/mL*hr. These data provide a standard of comparison for development of novel anti-toxins to replace DAT.

A Case of Localized, Unilateral (Cephalic) Wound Botulism.

We describe a rare presentation of botulism originally presenting with exclusively unilateral cranial nerve deficits following a puncture wound to the face. Cephalic tetanus was initially suspected but laboratory testing confirmed botulism. Botulism caused by local diffusion of toxin from a contaminated head wound can be confused with cephalic tetanus.

Diphtheria outbreak in Lao People's Democratic Republic, 2012-2013.

BACKGROUND: Diphtheria is a vaccine-preventable disease. When vaccination coverage and population immunity are low, outbreaks can occur. We investigated a diphtheria outbreak in Lao People's Democratic Republic that occurred during 2012-2013 and highlighted challenges in immunization services delivery to children in the country. METHODS: We reviewed diphtheria surveillance data from April 1, 2012-May 31, 2013. A diphtheria case was defined as a respiratory illness consisting of pharyngitis, tonsillitis, or laryngitis, and an adherent tonsillar or nasopharyngeal pseudomembrane. To identify potential risk factors for diphtheria, we conducted a retrospective case-control study with two aged-matched neighborhood controls per case-patient in Houaphan Province, using bivariate analysis to calculate matched odds ratio (mOR) with 95% confidence intervals (CI). Reasons for non-vaccination among unvaccinated persons were assessed. RESULTS: Sixty-two clinical cases of diphtheria and 12 diphtheria-related deaths were reported in seven of 17 provinces. Among case-patients, 43 (69%) were <15years old, five (8%) reported receiving three DTP doses (DTP3), 21 (34%) had received no DTP doses, and 35 (56%) had unknown vaccination status. For the case-control study, 42 of 52 diphtheria case-patients from Houaphan province and 79 matched-controls were enrolled. Five (12%) case-patients and 20 (25%) controls had received DTP3 (mOR=0.4, CI=0.1-1.7). No diphtheria toxoid-containing vaccine was received by 20 (48%) case-patients and 38 (46%) controls. Among case-patients and controls with no DTP dose, 43% of case-patients and 40% of controls lacked access to routine immunization services. CONCLUSION: Suboptimal DTP3 coverage likely caused the outbreak. To prevent continued outbreaks, access to routine immunization services should be strengthened, outreach visits need to be increased, and missed opportunities need to be minimized. In the short term, to rapidly increase population immunity, three rounds of DTP immunization campaign should be completed, targeting children aged 0-14years in affected provinces.

First pertussis vaccine dose and prevention of infant mortality.

BACKGROUND: American infants are at highest risk of severe pertussis and death. We investigated the role of ≥1 pertussis vaccinations in preventing pertussis-related deaths and risk markers for death among infants aged <42 days. METHODS: We analyzed characteristics of fatal and nonfatal infant pertussis cases reported nationally during 1991-2008. Infants were categorized into 2 age groups on the basis of eligibility to receive a first pertussis vaccine dose at age 6 weeks; dose 1 was considered valid if given ≥14 days before illness onset. Multivariable logistic regression was used to estimate the effect of ≥1 pertussis vaccine doses on outcome and risk markers. RESULTS: Pertussis-related deaths occurred among 258 of 45 404 cases. Fatal and nonfatal cases were confirmed by culture (54% vs 49%) and polymerase chain reaction (31% vs 27%). All deaths occurred before age 34 weeks at illness onset; 64% occurred before age 6 weeks. Among infants aged ≥42 days, receiving ≥1 doses of vaccine protected against death (adjusted odds ratio [aOR]: 0.28; 95% confidence interval [CI]: 0.11-0.74), hospitalization (aOR: 0.69; 95% CI: 0.63-0.77), and pneumonia (aOR: 0.80; 95% CI: 0.68-0.95). Risk was elevated for Hispanic ethnicity (aOR: 2.28; 95% CI: 1.36-3.83) and American Indian/Alaska Native race (aOR: 5.15; 95% CI: 2.37-11.2) and lower for recommended antibiotic treatment (aOR: 0.28; 95% CI: 0.16-0.47). Among infants aged <42 days, risk was elevated for Hispanic ethnicity and lower with recommended antibiotic use. CONCLUSIONS: The first pertussis vaccine dose and antibiotic treatment protect against death, hospitalization, and pneumonia.

Vaccine-preventable disease among homeschooled children: two cases of tetanus in Oklahoma.

Homeschooled children represent an increasing proportion of school-aged children in the United States. Immunization rates among homeschooled children are largely unknown because they are usually not subject to state-based school-entry vaccination requirements. Geographic foci of underimmunized children can increase the risk for outbreaks of vaccine-preventable diseases. In 2012, 2 cases of tetanus were reported in Oklahoma; both cases involved homeschooled children without documentation of diphtheria-tetanus-acellular pertussis vaccination. We describe the characteristics of both patients and outline innovative outreach measures with the potential to increase vaccination access and coverage among homeschooled children.

Prevention of pertussis, tetanus, and diphtheria among pregnant and postpartum women and their infants recommendations of the Advisory Committee on Immunization Practices (ACIP).

In 2005, two tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines were licensed and recommended for use in adults and adolescents in the United States: ADACEL (sanofi pasteur, Swiftwater, Pennsylvania), which is licensed for use in persons aged 11--64 years, and BOOSTRIX (GlaxoSmithKline Biologicals, Rixensart, Belgium), which is licensed for use in persons aged 10-18 years. Both Tdap vaccines are licensed for single-dose use to add protection against pertussis and to replace the next dose of tetanus and diphtheria toxoids vaccine (Td). Available evidence does not address the safety of Tdap for pregnant women, their fetuses, or pregnancy outcomes sufficiently. Available data also do not indicate whether Tdap-induced transplacental maternal antibodies provide early protection against pertussis to infants or interfere with an infant's immune responses to routinely administered pediatric vaccines. Until additional information is available, CDC's Advisory Committee on Immunization Practices recommends that pregnant women who were not vaccinated previously with Tdap: 1) receive Tdap in the immediate postpartum period before discharge from hospital or birthing center, 2) may receive Tdap at an interval as short as 2 years since the most recent Td vaccine, 3) receive Td during pregnancy for tetanus and diphtheria protection when indicated, or 4) defer the Td vaccine indicated during pregnancy to substitute Tdap vaccine in the immediate postpartum period if the woman is likely to have sufficient protection against tetanus and diphtheria. Although pregnancy is not a contraindication for receiving Tdap vaccine, health-care providers should weigh the theoretical risks and benefits before choosing to administer Tdap vaccine to a pregnant woman. This report 1) describes the clinical features of pertussis, tetanus, and diphtheria among pregnant and postpartum women and their infants, 2) reviews available evidence of pertussis vaccination during pregnancy as a strategy to prevent infant pertussis, 3) summarizes Tdap vaccination policy in the United States, and 4) presents recommendations for use of Td and Tdap vaccines among pregnant and postpartum women.

Investigations of 2 cases of diphtheria-like illness due to toxigenic Corynebacterium ulcerans.

BACKGROUND: We present 2 case reports in the United States and investigations of diphtheria-like illness caused by toxigenic Corynebacterium ulcerans. A fatal case occurred in a 75-year-old male Washington resident who was treated with clindamycin but did not receive equine diphtheria antitoxin. A second, nonfatal case occurred in a 66-year-old female Tennessee resident who received erythromycin and diphtheria antitoxin. METHODS: Both case patients and close human and animal contacts were investigated by their respective state health departments. RESULTS: C. ulcerans isolated from the patient who died was resistant to erythromycin and clindamycin. For both isolates, conventional polymerase chain reaction results were positive for A and B subunits of diphtheria toxin gene tox, and modified Elek tests confirmed toxin production. The source of infection remained undetermined for both cases. Neither patient was up-to-date with diphtheria toxoid vaccination. CONCLUSION: These case reports highlight the importance of early treatment with diphtheria antitoxin, the selection of effective antimicrobial agents, and prevention through up-to-date vaccination.

Analysis of toxigenic Corynebacterium ulcerans strains revealing potential for false-negative real-time PCR results.

Diphtheria surveillance depends on the rapid and reliable recognition of the toxin gene in Corynebacterium diphtheriae. Real-time PCR is a rapid tool to confirm the presence of the diphtheria toxin gene (tox) in an isolate or specimen. We report that some toxigenic Corynebacterium ulcerans strains show atypical results in a real-time PCR for tox.

Two nosocomial pertussis outbreaks and their associated costs - King County, Washington, 2004.

OBJECTIVE: Pertussis outbreaks in healthcare settings result in resource-intensive control activities, but studies have rarely evaluated the associated costs. We describe and estimate costs associated with 2 nosocomial pertussis outbreaks in King County, Washington, during the period from July 25 to September 15, 2004. One outbreak occurred at a 500-bed tertiary care hospital (hospital A), and the other occurred at a 250-bed pediatric hospital (hospital B). METHODS: We estimated the costs of each outbreak from the hospitals' perspective through standardized interviews with hospital staff and review of contact tracing logs. Direct costs included personnel time and laboratory and medication costs, whereas indirect costs were those resulting from hospital staff furloughs. RESULTS: Hospital A incurred direct costs of $195,342 and indirect costs of $68,015; hospital B incurred direct costs of $71,130 and indirect costs of $50,000. Cost differences resulted primarily from higher personnel costs at hospital A ($134,536), compared with hospital B ($21,645). Total cost per pertussis case was $43,893 for hospital A (6 cases) and $30,282 for hospital B (4 cases). Total cost per person exposed to a pertussis patient were $357 for hospital A (738 exposures) and $164 for hospital B (737 exposures). CONCLUSIONS: Nosocomial pertussis outbreaks result in substantial costs to hospitals, even when the number of pertussis cases is low. The cost-effectiveness of strategies to prevent nosocomial pertussis outbreaks, including vaccination of healthcare workers, should be evaluated.

Preventing tetanus, diphtheria, and pertussis among adults: use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine recommendations of the Advisory Committee on Immunization Practices (ACIP) and recommendation of ACIP, supported by the Healthcare Infection Control Practices Advisory Committee (HICPAC), for use of Tdap among health-care personnel.

On June 10, 2005, a tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine (Tdap) formulated for use in adults and adolescents was licensed in the United States for persons aged 11-64 years (ADACEL, manufactured by sanofi pasteur, Toronto, Ontario, Canada). Prelicensure studies demonstrated safety and efficacy, inferred through immunogenicity, against tetanus, diphtheria, and pertussis when Tdap was administered as a single booster dose to adults. To reduce pertussis morbidity among adults and maintain the standard of care for tetanus and diphtheria prevention and to reduce the transmission of pertussis to infants and in health-care settings, the Advisory Committee on Immunization Practices (ACIP) recommends that: 1) adults aged 19-64 years should receive a single dose of Tdap to replace tetanus and diphtheria toxoids vaccine (Td) for booster immunization against tetanus, diphtheria, and pertussis if they received their last dose of Td >or=10 years earlier and they have not previously received Tdap; 2) intervals shorter than 10 years since the last Td may be used for booster protection against pertussis; 3) adults who have or who anticipate having close contact with an infant aged <12 months (e.g., parents, grandparents aged <65 years, child-care providers, and health-care personnel) should receive a single dose of Tdap to reduce the risk for transmitting pertussis. An interval as short as 2 years from the last Td is suggested; shorter intervals can be used. When possible, women should receive Tdap before becoming pregnant. Women who have not previously received Tdap should receive a dose of Tdap in the immediate postpartum period; 4) health-care personnel who work in hospitals or ambulatory care settings and have direct patient contact should receive a single dose of Tdap as soon as feasible if they have not previously received Tdap. An interval as short as 2 years from the last dose of Td is recommended; shorter intervals may be used. These recommendations for use of Tdap in health-care personnel are supported by the Healthcare Infection Control Practices Advisory Committee (HICPAC). This statement 1) reviews pertussis, tetanus and diphtheria vaccination policy in the United States; 2) describes the clinical features and epidemiology of pertussis among adults; 3) summarizes the immunogenicity, efficacy, and safety data of Tdap; and 4) presents recommendations for the use of Tdap among adults aged 19-64 years.

Preventing tetanus, diphtheria, and pertussis among adolescents: use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccines recommendations of the Advisory Committee on Immunization Practices (ACIP).

During spring 2005, two tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine (Tdap) products formulated for use in adolescents (and, for one product, use in adults) were licensed in the United States (BOOSTRIX, GlaxoSmithKline Biologicals, Rixensart, Belgium [licensed May 3, 2005, for use in persons aged 10-18 years], and ADACEL, sanofi pasteur, Toronto, Ontario, Canada [licensed June 10, 2005, for use in persons aged 11-64 years]). Prelicensure studies demonstrated safety and efficacy against tetanus, diphtheria, and pertussis when Tdap was administered as a single booster dose to adolescents. To reduce pertussis morbidity in adolescents and maintain the standard of care for tetanus and diphtheria protection, the Advisory Committee on Immunization Practices (ACIP) recommends that: 1) adolescents aged 11-18 years should receive a single dose of Tdap instead of tetanus and diphtheria toxoids vaccine (Td) for booster immunization against tetanus, diphtheria, and pertussis if they have completed the recommended childhood diphtheria and tetanus toxoids and whole cell pertussis vaccine (DTP)/ diphtheria and tetanus toxoids and acellular pertussis vaccine (DTaP) vaccination series (five doses of pediatric DTP/DTaP before the seventh birthday; if the fourth dose was administered on or after the fourth birthday, the fifth dose is not needed) and have not received Td or Tdap. The preferred age for Tdap vaccination is 11-12 years; 2) adolescents aged 11-18 years who received Td, but not Tdap, are encouraged to receive a single dose of Tdap to provide protection against pertussis if they have completed the recommended childhood DTP/DTaP vaccination series. An interval of at least 5 years between Td and Tdap is encouraged to reduce the risk for local and systemic reactions after Tdap vaccination. However, an interval less than 5 years between Td and Tdap can be used; and 3) vaccine providers should administer Tdap and tetravalent meningococcal conjugate vaccine (Menactra, sanofi pasteur, Swiftwater, Pennsylvania) to adolescents aged 11-18 years during the same visit if both vaccines are indicated and available. This statement 1) reviews tetanus, diphtheria and pertussis vaccination policy in the United States, with emphasis on adolescents; 2) describes the clinical features and epidemiology of pertussis among adolescents; 3) summarizes the immunogenicity, efficacy, and safety data of the two Tdap vaccines licensed for use among adolescents; and 4) presents recommendations for tetanus, diphtheria, and pertussis vaccination among adolescents aged 11-18 years.

Nosocomial pertussis: costs of an outbreak and benefits of vaccinating health care workers.

BACKGROUND: In September 2003, 17 symptomatic cases of pertussis among health care workers (HCWs) resulted from a 1-day exposure to an infant who was later confirmed to have pertussis. These HCWs identified 307 close contacts. The hospital implemented extensive infection-control measures. The objective of this study was to determine direct and indirect costs incurred by the hospital and symptomatic HCWs as a result of the September 2003 outbreak and to estimate possible benefits of vaccinating HCWs from the hospital perspective. METHODS: We determined costs by interviewing infection-control and hospital personnel, reviewing billing records, and surveying symptomatic HCWs. We calculated the benefits and costs of a vaccination program for HCWs, using a probabilistic model to estimate the number of pertussis exposures that would require control measures annually. Sensitivity and threshold analyses were performed. RESULTS: The outbreak cost to the hospital was 74,870 dollars. The total measured cost of the outbreak was 81,382 dollars, including costs incurred by HCWs (6512 dollars). Our model predicted that vaccinating HCWs against pertussis would prevent >46% of exposures from HCWs with pertussis per year and would provide net savings. The benefit for the hospital was estimated to be 2.38 times the dollar amount invested in vaccinating HCWs. The number of exposures prevented and the benefit-cost ratio were sensitive to the number of exposures identified, the incidence of pertussis among HCWs, and HCW turnover. CONCLUSIONS: A single nosocomial pertussis outbreak resulted in substantial disruption and costs to the hospital and to HCWs. Our model suggests that cost savings and benefits could be accrued by vaccinating HCWs against pertussis.

Recommended antimicrobial agents for the treatment and postexposure prophylaxis of pertussis: 2005 CDC Guidelines.

The recommendations in this report were developed to broaden the spectrum of antimicrobial agents that are available for treatment and postexposure prophylaxis of pertussis. They include updated information on macrolide agents other than erythromycin (azithromycin and clarithromycin) and their dosing schedule by age group.

Forty years of disinfectant failure: outbreak of postinjection Mycobacterium abscessus infection caused by contamination of benzalkonium chloride.

Benzalkonium chloride (BC) continues to be used as an antiseptic and contributes to serious outbreaks of disease. In July 1999, 6 postinjection joint infections caused by Mycobacterium abscessus were reported to the Texas Department of Health (Austin). We investigated this outbreak and identified 12 case patients who had been seen by the same physician and who had received an intra-articular or periarticular steroid injection during the period of 1 April through 31 July 1999. M. abscessus was cultured from either joint fluid or periarticular soft-tissue specimens obtained from 10 patients. We cultured environmental samples, and we compared isolates recovered from case patients with environmental isolates by pulsed-field gel electrophoresis and randomly amplified polymorphic DNA polymerase chain reaction (RAPD-PCR). Four environmental samples containing diluted BC yielded M. abscessus. Clinical and environmental strains of M. abscessus were indistinguishable by RAPD-PCR. The case patients' strain was resistant to BC. The use of BC as an antiseptic should be discontinued.