PMC10183579_01
Representative results of sample culture and antibiotic susceptibility testing in patients. (A) On day 14, P. aeruginosa was positive in the blood culture and bacterial culture of wound tissues. (B) On day 28, tiny, nonhemolytic, and transparent colonies were observed on the Columbia blood agar plate. (C) Fried-egg-type colonies were observed on mycoplasma medium after 5 days of incubation. (D) The results of antibiotic susceptibility testing showed that M. hominis was susceptible to doxycycline, minocycline, and josamycin but resistant to azithromycin, clarithromycin, norfloxacin, ciprofloxacin, roxithromycin, sparfloxacin, spectinomycin, and levofloxacin.
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On day 14, P. aeruginosa was positive in the bacterial culture of wound tissues ( Figure 1A ) and was identified as a multiple-resistant strain with antibiotic susceptibility testing (AST; Kirby-Bauer method), thus amikacin (0.4 g/day) was added to the anti-infective regimen. On day 26, tiny, nonhemolytic, and transparent colonies grew on the Columbia blood agar plate of four blood sample cultures ( Figure 1B ), possibly representing M. hominis. A subculture of blood and wound tissue samples on mycoplasma medium presents as fried-egg-type colonies after 5 days of incubation ( Figure 1C ). The AST with a commercial kit (broth dilution method, Zhongaisheng, Hebei, China) showed that M. hominis was susceptible to doxycycline, minocycline, and josamycin but resistant to azithromycin, clarithromycin, norfloxacin, ciprofloxacin, roxithromycin, sparfloxacin, spectinomycin, and levofloxacin ( Figure 1D ).
Phylogenetic analyses of M. hominis isolated from wound tissue and blood samples.
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Colonies were then identified to be M. hominis by the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and further confirmed by 16S rRNA sequencing (primers: 27F, AGAGTTTGATCMTGGCTCAG; 1492R, GGTTACCTTGTTACGACTT) and phylogenetic tree analysis ( Figure 2 ; GenBank Accession No.
Timelines of patient's diagnosis and treatment. Red, the anti-infective drugs for P. aeruginosa. Blue, the anti-infective drugs for M. hominis. Abbreviations: CXM, cefuroxime; CSL, cefoperazone-sulbactam; LVX, levofloxacin; MEM, meropenem; TEC, teicoplanin; AMK, amikacin; MFX, moxifloxacin; CAZ-AVI, ceftazidime-avibactam; POL, polymyxin B; MNO, minocycline.
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Details regarding the diagnosis and treatment are shown in  Figure 3 .