Staphylococcus xylosus Cystitis and Struvite Urolithiasis in Nude Mice Implanted with Sustained-release Estrogen Pellets

Abstract

Female nude mice (J:NU-Foxn1nu; age, 6 wk) were injected with 1 million MCF7 human breast cancer cells in the fourth mammary fat pads and received a 21-d sustained-release estrogen pellet (0.25 mg) subcutaneously in the dorsum of the neck. All mice were maintained in sterile housing and provided sterile water and irradiated rodent chow. Approximately 6 wk after implantation, 4 of the 30 mice showed clinical signs of depression and dehydration. The 2 animals most severely affected were euthanized and presented for necropsy. The urinary bladders of these animals were distended with variable sized white, opaque uroliths. Urinalysis revealed coccal bacteria, erythrocytes, neutrophils and struvite crystals. Urine cultures from both necropsied animals grew heavy, pure growths of Staphylococcus xylosus. The organism was sensitive to all antibiotics tested except erythromycin (intermediate). Analysis of the uroliths revealed 100% struvite composition. Remaining mice in the study were evaluated clinically for hydration status, the ability to urinate, and the presence of palpable stones in the urinary bladder; one additional mouse had a firm, nonpainful bladder (urolithiasis suspected). Given the sensitivity of the organisms cultured from urine samples, the remaining mice were placed on enrofloxacin in the drinking water (0.5 mg/mL). All remaining mice completed the study without further morbidity or mortality. Previous studies have reported the association of estrogen supplementation with urinary bladder pathology, including infection and urolithiasis. Here we present a case of urolithiasis and cystitis in nude mice receiving estrogen supplementation that was associated with Staphylococcus xylosus, which previously was unreported in this context. When assessing these nude mice for urolithiasis, we found that visualizing the stones through the body wall, bladder palpation, and bladder expression were helpful in identifying affected mice.

Evaluation of an 131I-labeled HER2-specific single domain antibody fragment for the radiopharmaceutical therapy of HER2-expressing cancers

“…One CR also was observed in both the 18 and 10 MBq groups. Unfortunately, most mice developed complications from estrogen pellet-induced urolithiasis, a known complication of this model 25 , and died. Two mice in the control group, and 4, 9 and 7 in the 10, 18, and 30 MBq groups, respectively, died due to toxicity caused by urolithiasis as determined by necropsy.…”

PCR Prevalence of Murine Opportunistic Microbes and their Mitigation by Using Vaporized Hydrogen Peroxide

“…These findings extend prior reports regarding the utility of PCR testing of IVC exhaust airways as a component of murine health surveillance 2,12,24,31,39,44,45 and are especially applicable to improved health monitoring of immunodeficient mice, in which such agents serve as opportunistic pathogens. 1,5,15,20,56,58,59,74 Although sanitization by mechanized washing reduced the PCR evidence of these microbes, most species (that is, 5 of the 8 obtained) remained PCR-detectable. VHP exposure with equipment left unassembled (that is, in the static-open configuration) did not substantively further reduce the PCR evidence of microbes in exhaust plenums.…”

“…As immunodeficient and genetically engineered mice comprise an ever larger portion of murine inventories, microbes to be monitored in murine facilities will likely expand to include opportunistic microbes, members of the microbiome, and new, previously unrecognized microbial pathogens. 1,5,6,11,15,[18][19][20]39,40,43,46,56,[58][59][60]62,63,74 We recently demonstrated that active-closed VHP sterilization of secondary housing equipment was an important component to facilitywide eradication of Corynebacterium bovis, 43 perhaps one of the more problematic opportunistic outbreaks in an immunodeficient murine colony. Our prior report described that despite the absence of marked, widespread morbidity attributable to Corynebacterium bovis, this organism can be harbored by a number of immunodeficient strains, is PCR-identifiable among unaffected immunocompetent strains, and is broadly disseminated to all facility areas during an outbreak.…”

“…and Klebsiella oxytoca can cause nephritis, 15 and the opportunist Pasteurella pneumotropica may cause pneumonia in aged NSG mice. 59 In addition, the murine skin commensal Staphylococcus xylosus can cause dermatitis, abscess formation, or cystitis in immunodeficient strains, 1,5,20,56,58 and the opportunist Corynebacterium bovis causes hyperkeratotic acanthotic dermatitis in nude mice 11 and skin disease in haired Pkrdc scid mice 60 and hairless immunocompetent SKH1-Hr hr mice 19 and becomes disseminated facilitywide. 6,43 Moreover, a number of microbes either harbored by humans or common to the environment are opportunistic pathogens in immunodeficient mice, including Pseudomonas aeruginosa, β-hemolytic Streptococcus spp., Staphylococcus aureus, and Pneumocystis carinii.…”

Effectiveness of Various Floor Contamination Control Methods in Reducing Environmental Organic Load and Maintaining Colony Health in Rodent Facilities

“…Bacterial transfer experiment. Staphylococcus xylosus, an environmentally persistent commensal bacterial strain 15,20 found on the skin of humans and animals, was collected from the skin of 2 colony mice and cultured on trypticase soy agar with 5% sheep blood (TSA II; Becton Dickinson, Franklin Lakes, NJ). Pure cultures of S. xylosus were confirmed by using physical and biochemical methods and then verified through PCR analysis.…”