Coinfection With Lophomonas spp. and Streptococcus pyogenes Presenting as Atypical Pneumonia in a Patient With Poorly Controlled Type 1 Diabetes Mellitus: A Case Report From Mexico.

Pulmonary lophomoniasis is a rare protozoal infection caused by Lophomonas spp., anaerobic, flagellated organisms that inhabit the gastrointestinal tract of cockroaches. Lophomonas blattarum is considered a public health concern due to its involvement in human bronchopulmonary infections. In contrast, Streptococcus pyogenes, a Gram-positive bacterium commonly associated with pharyngitis and invasive infections, plays an unusual role in pneumonia. To our knowledge, this represents the first documented case of coinfection involving Lophomonas spp. and S. pyogenes, rendering this case atypical. We present the case of a 28-year-old female patient with type 1 diabetes mellitus and persistent poor glycemic control, who developed pneumonia concomitant with Lophomonas spp. and S. pyogenes infection and was admitted to La Concepción Hospital in Saltillo, Coahuila, Mexico. Initial chest computed tomography (CT) revealed pleural effusion and pulmonary consolidations, prompting further microbiological and immunological investigations. The presence of Lophomonas spp. was confirmed through bronchoalveolar lavage, which led to the initiation of metronidazole therapy. Despite initial symptom resolution, the patient experienced recurrent symptoms, and a polymerase chain reaction (PCR) panel identified S. pyogenes, necessitating adjustment of antibiotic therapy. This case highlights the diagnostic challenges of pulmonary lophomoniasis and underscores the importance of considering potential bacterial coinfections, particularly in immunocompromised patients such as those with poorly controlled type 1 diabetes mellitus.