Lactobacillus Bacteremia: A Challenging Condition for Pediatrician

To the Editors: Invasive infections due to Lactobacillus spp. are rare, especially in children, but can occur in predisposed hosts, notably those with central venous catheters (CVCs).1 We report 2 pediatric cases of Lactobacillus rhamnosus CVC-related bacteremia admitted to our hospital, highlighting risk factors and therapeutic considerations. Case 1 A 5-month-old male with growth delay and genetic deletion (del4q12q21.22) requiring prolonged hospitalization and parenteral nutrition via CVC. The patient was receiving Lactobacillus rhamnosus probiotics through a nasogastric tube. After prior Staphylococcus hominis CVC sepsis treated with vancomycin (without catheter removal), he developed fever and mild C-reactive protein increase (11.1 mg/L). Blood cultures from CVC and periphery grew Lactobacillus rhamnosus (Table 1), suggesting CVC-related infection. According to the antibiogram and literature,2 vancomycin was replaced by clindamycin, and probiotics were stopped. Echocardiogram excluded endocarditis. Twelve days after fever onset, CVC was removed. The patient received 4 weeks of intravenous antibiotics with full recovery and no relapse. TABLE 1. - Antibiograms of Positive Blood Culture for Lactobacillus Rhamnosus Antibiotics Case 1 Case 2 MIC MIC Penicicillin G R 0.75 I 1 Piperacillin-tazobactam 0.75 Meropenem R >32 Clindamycin 0.125 IE 0.125 Vancomycin R >256 Metronidazole R Ampicillin S 1 Imipenem S 1.5 Erythromycin IE 0.047 European Committee on Antimicrobial Susceptibility Testing Criteria for Lactobacillus Rhamnosus are not available.I indicates susceptible to high dosage; IE, insufficient evidence; R, resistant; S, susceptible. Case 2 A 3-month-old male with pulmonary atresia and ductal stenting presented with fever and high inflammatory markers (C-reactive protein 148.9 mg/L, procalcitonin 15.24 mcg/L) 2 weeks after CVC placement for anticoagulant therapy due to stent thrombosis. No probiotics had been administered. Blood cultures from CVC grew Lactobacillus rhamnosus, sensitive to ampicillin and imipenem (Table 1). Therapy was switched to clindamycin and ampicillin-sulbactam; clindamycin was stopped after 6 days due to hepatotoxicity. After slow improvement, CVC was removed after 12 days; the tip culture was negative. Ampicillin-sulbactam was continued for 14 days, then replaced by oral Clindamycin to complete 4 weeks. No recurrence was observed. Lactobacillus rhamnosus is generally considered low pathogenic but can cause invasive infections in vulnerable hosts, particularly with intravascular devices.1,3 Pediatric data are scarce; most reports involve neonates or children with major comorbidities.4 In both cases, risk factors included long-term CVC and underlying disease. Probiotic intake was noted only in the first patient, confirming that bacteremia may also occur independently of supplementation, as supported by previous studies.2,3 Management is challenging due to a lack of European Committee on Antimicrobial Susceptibility Testing breakpoints and typical resistance to glycopeptides, notably vancomycin.1,2 Our first strain was resistant to vancomycin; the second was susceptible to beta-lactams. Literature supports clindamycin and beta-lactams, sometimes combined, based on susceptibility testing.1,2 Device removal, when feasible, is crucial, given the biofilm-forming ability of Lactobacillus.3 Duration of therapy is not standardized; in our experience, treatment of at least 2 weeks after catheter removal or replacement ensured cure without relapse, aligning with recommendations for Gram-positive CVC-related infections.5 Though rare, Lactobacillus bacteremia should be considered in at-risk pediatric patients with CVCs. Rational use of probiotics, careful monitoring, timely CVC removal, and targeted combination therapy based on susceptibility testing appear key for successful outcomes.