Brief report: meningitis due to iatrogenic BCG infection in two immunocompromised children

Bacille Calmette-Guérin preparation and intravesical administration to patients with bladder cancer: Risks to healthcare personnel and patients, and mitigation strategies

Intravesical Bacillus Calmette-Guérin (BCG) is a standard therapy for non-muscle-invasive bladder cancer used in urology clinics and inpatient settings. We present a review of infection risks to patients receiving intravesical BCG, healthcare personnel who prepare and administer BCG, and other patients treated in facilities where BCG is prepared and administered. Knowledge of these risks and relevant regulations informs appropriate infection prevention measures.

Case Report: Acquired Disseminated BCG in the Context of a Delayed Immune Reconstitution After Hematological Malignancy

Context

Disseminated infections due to Mycobacterium bovis Bacillus Calmette-Guérin (BCG) are unusual and occur mostly in patients with inborn error of immunity (IEI) or acquired immunodeficiency. However, cases of secondary BCGosis due to intravesical BCG instillation have been described. Herein, we present a case of severe BCGosis occurring in an unusual situation.

Case Description

We report one case of severe disseminated BCG disease occurring after hematological malignancy in a 48-year-old man without BCG instillation and previously vaccinated in infancy with no complication. Laboratory investigations demonstrated that he was not affected by any known or candidate gene of IEI or intrinsic cellular defect involving IFNγ pathway. Whole genome sequencing of the BCG strain showed that it was most closely related to the M. bovis BCG Tice strain, suggesting an unexpected relationship between the secondary immunodeficiency of the patient and the acquired BCG infection.

Conclusion

This case highlights the fact that, in addition to the IEI, physicians, as well as microbiologists and pharmacists should be aware of possible acquired disseminated BCG disease in secondary immunocompromised patients treated in centers that administrate BCG for bladder cancers.

Bovine Tuberculosis: A Re-emerging Zoonotic Infection

Bovine tuberculosis is caused by Mycobacterium bovis (M. bovis), which infects both humans and cattle. In 2018, a dairy farm in Wisconsin was affected by M. bovis, including a farmworker with exposure to the affected herd. Largely eradicated by effective public health strategies in the United States, most cases are now associated with risk factors including occupational hazards, food consumption, and iatrogenic infections. M. bovis continues to cause disease worldwide affecting certain at-risk populations in the United States. Infections more often result in extrapulmonary sequelae and resistance to pyrazinamide is universal. Thus, successful treatment depends on early and correct identification of the mycobacterium species. A One Health approach to control this re-emerging disease is crucial.

Healthcare-Associated Mycobacterium bovis-Bacille Calmette-Guérin (BCG) Infection in Cancer Patients Without Prior BCG Instillation

Background

Bacille Calmette-Guérin (BCG), an attenuated strain of Mycobacterium bovis, is widely used as adjunctive therapy for superficial bladder cancer. Intravesical administration of BCG has been associated with systemic infection. Disseminated infection due to M. bovis is otherwise uncommon.

Methods

After identification of 3 patients with healthcare-associated BCG infection who had never received intravesical BCG administration, an epidemiologic study was performed. All patients with healthcare-associated BCG infection in the Barcelona tuberculosis (TB) program were reviewed from 1 January 2005 to 31 December 2015, searching for infections caused by M. bovis-BCG. Patients with healthcare-associated BCG infection who had not received intravesical BCG instillation were selected and the source of infection was investigated.

Results

Nine oncology patients with infection caused by M. bovis-BCG were studied. All had permanent central venous catheters. Catheter maintenance was performed at 4 different outpatient clinics in the same room in which other patients underwent BCG instillations for bladder cancer without required biological precautions. All patients developed pulmonary TB, either alone or with extrapulmonary disease. Catheter-related infection was considered the mechanism of acquisition based on the epidemiologic association and positive catheter cultures for BCG in patients in whom mycobacterial cultures were performed.

Conclusions

Physicians should be alerted to the possibility of TB due to nosocomially acquired, catheter-related infections with M. bovis-BCG in patients with indwelling catheters. This problem may be more common than expected in centers providing BCG therapy for bladder cancer without adequate precautions.

Mycobacterium bovis BCG spinal osteomyelitis in a patient with bladder cancer without a history of BCG instillation

BCG has been used as intravesical immunotherapy for the treatment of bladder carcinoma. However, this treatment is not harmless and may lead to complications, with a reported incidence of systemic BCG infection ranging from 3% to 7%. We report a case of culture-proven Mycobacterium bovis (BCG) vertebral osteomyelitis in a 72-year-old patient with bladder carcinoma who was treated with intravesical mitomycin C but did not receive BCG. Cultures from biopsy recovered isolate resembling Mycobacterium tuberculosis biochemically, but resistant to pyrazinamide (PZA). The patient was originally started on a four-drug antituberculous regimen of isoniazid, rifampin, ethambutol and PZA. After genotypic analysis identified the organism as M. bovis (BCG), the regimen was changed to isoniazid and rifampin for 12 months. The patient responded well to this treatment. This case is unique as the patient received only intravesical mitomycin and did not receive BCG, implying the possibility of transmission from contaminated equipment.

Zoonotic bacterial meningitis in human adults

OBJECTIVE

To describe the epidemiology, etiology, clinical characteristics, treatment, outcome, and prevention of zoonotic bacterial meningitis in human adults.

METHODS

We identified 16 zoonotic bacteria causing meningitis in adults.

RESULTS

Zoonotic bacterial meningitis is uncommon compared to bacterial meningitis caused by human pathogens, and the incidence has a strong regional distribution. Zoonotic bacterial meningitis is mainly associated with animal contact, consumption of animal products, and an immunocompromised state of the patient. In a high proportion of zoonotic bacterial meningitis cases, CSF analysis showed only a mildly elevated leukocyte count. The recommended antibiotic therapy differs per pathogen, and the overall mortality is low.

CONCLUSIONS

Zoonotic bacterial meningitis is uncommon but is associated with specific complications. The suspicion should be raised in patients with bacterial meningitis who have recreational or professional contact with animals and in patients living in regions endemic for specific zoonotic pathogens. An immunocompromised state is associated with a worse prognosis. Identification of risk factors and underlying disease is necessary to improve treatment.

Mycobacterium bovis Cerebellar Abscess Following Treatment With Bacillus Calmette-Guérin

Bacillus Calmette-Guérin (BCG) is a live, attenuated strain of Mycobacterium bovis that is used to treat superficial bladder cancer. Although its use is typically associated with only mild, localized side effects, rare systemic complications can occur. Disseminated mycobacterium infections after BCG therapy have been reported in over 30 cases; however, central nervous system (CNS) infections do not commonly occur. We report a 74-year-old male who developed a M. bovis cerebellar abscess after receiving intravesical BCG infusion for bladder cancer for less than 1 year. This patient was successfully treated with antituberculosis therapy and corticosteroids. This patient case demonstrates that early-onset M bovis CNS infections can occur after BCG therapy. Patients presenting with altered mental status while on BCG therapy should be evaluated for disseminated infections.

Infected Aortic Aneurysm caused by Mycobacterium bovis after Intravesical Bacillus Calmette-Guérin Treatment for Bladder Cancer

A 70-year-old man presented with lower back pain and cyanotic changes in his left lower extremity. He was diagnosed with infected aortic aneurysm and infectious spondylitis. He had received intravesical Bacillus Calmette-Guérin (BCG) therapy up to 1 month before the onset of symptoms. The aneurysm was excised and an aorto-biiliac interposition graft was performed. Mycobacterium tuberculosis complex was cultured in the surgical specimens. Real-time polymerase chain reaction (PCR) targeting the senX3-regX3 region, and multiplex PCR using dual-priming oligonucleotide primers targeting the RD1 gene, revealed that the organism isolated was Mycobacterium bovis BCG. The patient took anti-tuberculosis medication for 1 year, and there was no evidence of recurrence at 18 months follow-up.

Disruption of the gene encoding for secretion antigen SA5K affects growth of Mycobacterium bovis bacillus Calmette-Guerin in human macrophages and in mice

An 8.3-kDa secretory antigen of Mycobacterium bovis bacillus Calmette-Guerin (BCG), called SA5K, was previously identified and characterized in our laboratory. Sequence analysis of the BCG sa5k gene, including the corresponding promoter region, showed that it is identical to the homologous gene in Mycobacterium tuberculosis (Rv1174c). No significant homology with other proteins was found and the physiologic role of SA5K for mycobacteria remains unknown. In the present study, a BCG mutant strain (BCGsa5k::aph) was constructed by allelic exchange involving the replacement of the sa5k gene with a kanamycin-inactivated copy. Mutant and parental strains showed similar growth rates in liquid medium, suggesting that the loss of the sa5k gene does not affect the in vitro growth of BCG. Nevertheless, BCGsa5k::aph showed a reduced ability to grow in human macrophages compared with the wild-type BCG, suggesting that SA5K is involved in intracellular survival/multiplication mechanisms. The mutant strain was also attenuated in vivo in a mouse infection model, showing impaired growth/survival in spleen and liver and fewer and smaller granulomatous lesions compared to the parental strain. Complementation of the mutation restored the parental phenotype. Taken together, results presented in this study suggest a role for SA5K in the growth capacity of BCG both in an intracellular milieu and in infected mice.

Reactivation of the bacille Calmette-Guérin scar following immune reconstitution during treatment of infant acute lymphoblastic leukemia

The authors describe an infant presenting at 2 weeks of age with congenital acute lymphoblastic leukemia who had previously received routine bacille Calmette-Guérin (BCG) vaccination at birth. The risk of BCG dissemination in immunocompromised infants is discussed and the use of antimycobacterial prophylaxis in such cases considered.

Mycobacterium bovis BCG recA deletion mutant shows increased susceptibility to DNA-damaging agents but wild-type survival in a mouse infection model

Pathogenic microorganisms possess antioxidant defense mechanisms for protection from reactive oxygen metabolites which are generated during the respiratory burst of phagocytic cells. These defense mechanisms include enzymes such as catalase, which detoxifies reactive oxygen species, and DNA repair systems, which repair damage resulting from oxidative stress. To (i) determine the relative importance of the DNA repair system when oxidative stress is encountered by the Mycobacterium tuberculosis complex during infection of the host and to (ii) provide improved mycobacterial hosts as live carriers to express foreign antigens, the recA locus was inactivated by allelic exchange in Mycobacterium bovis BCG. The recA mutants are sensitive to DNA-damaging agents and show increased susceptibility to metronidazole, the first lead compound active against the dormant M. tuberculosis complex. Surprisingly, the recA genotype does not affect the in vitro dormancy response, nor does the defect in the DNA repair system lead to attenuation as determined in a mouse infection model. The recA mutants will be a valuable tool for further development of BCG as an antigen delivery system to express foreign antigens and as a source of a genetically stable vaccine against tuberculosis.

Molecular epidemiology of tuberculosis and other mycobacterial infections: main methodologies and achievements

In the last decade, DNA fingerprint techniques have become available to study the interperson transmission of tuberculosis and other mycobacterial infections. These methods have facilitated epidemiological studies at a population level. In addition, the species identification of rarely encountered mycobacteria has improved significantly. This article describes the state of the art of the main molecular typing methods for Mycobacterium tuberculosis complex and non-M. tuberculosis complex (atypical) mycobacteria. Important new insights that have been gained through molecular techniques into epidemiological aspects and diagnosis of mycobacterial diseases are highlighted.

Nosocomial transmission of Mycobacterium bovis bacille Calmette-Guerin to children receiving cancer therapy and to their health care providers

A previous report of nosocomial infection due to Mycobacterium bovis bacille Calmette-Guerin (BCG) implicated contamination of chemotherapy solutions reconstituted under the same biosafety hood as BCG vaccine used for bladder cancer therapy. We report 3 similar BCG infections in children and describe evidence of respiratory transmission to health care workers (HCWs) from 1 patient. These children were receiving chemotherapy for leukemia when they presented with active tuberculosis. Each isolate was identified biochemically and by both gas-liquid chromatography and major polymorphic tandem repeat-polymerase chain reaction. Pulsed-field gel electrophoresis showed that 2 isolates were identical strains and identical to the Tice and Connaught strains licensed in the United States for bladder chemotherapy. The third isolate differed by a single fragment after DraI restriction. One patient with heavily positive sputum exposed numerous HCWs. Of 41 HCWs, 2 (5%) converted their purified protein derivatives (PPD) skin test. These data underscore the risk of nosocomial BCG transmission by contamination of chemotherapy solutions and demonstrate the potential for transmission to HCWs from patients with active pulmonary disease.

PCR identification of Mycobacterium bovis BCG

The attenuated bacillus Calmette-Guérin (BCG) vaccine strain is derived from a virulent strain of Mycobacterium bovis. BCG is difficult to differentiate from other strains of M. bovis and other members of the M. tuberculosis complex by conventional methods. Recently, a genomic region designated RD1 was found to be present in all virulent M. bovis and M. tuberculosis strains tested but deleted from all BCG strains tested. With this information, a multiplex PCR method was developed to detect the RD1 deletion. A large collection of BCG and other M. tuberculosis complex strains from diverse host and geographic origins was tested. RD1 was deleted in 23 of 23 BCG strains. RD1 was present in 129 of 129 other M. tuberculosis complex strains. This multiplex PCR method can be used as a tool for the rapid and specific identification of BCG.