Background/Aims: The pathophysiology of refractory gastroesophageal reflux disease (RGERD), which differs from proton pump inhibitor dependent gastroesophageal reflux disease (DGERD), remains incompletely elucidated. This study aims to compare esophageal motility patterns, transdiaphragmatic pressure gradients (TPG), and reflux profiles between RGERD and DGERD patients, and to delineate dynamic pressure gradient-esophagogastric junction (EGJ) interactions in these patients. Methods: In this retrospective study, 274 patients who underwent 24-hour impedance-pH monitoring and high-resolution manometry, along with an assessment of proton pump inhibitor responsiveness, were classified as RGERD (32.5%), DGERD (54.4%), or non-GERD (13.1%). Clinical characteristics, TPG, esophageal motility, and reflux metrics were compared between RGERD and DGERD patients. Subgroup analysis excluding hiatal hernia (HH) was conducted to investigate the pathophysiology of RGERD. Results: The RGERD group exhibited a significantly higher proportion of chest pain compared to the DGERD group. Regarding reflux profiles, RGERD patients without HH (RGERDHH- group) experienced increased weakly acidic reflux (P < 0.001) and prolonged bolus exposure (P = 0.006) compared to their counterparts (DGERDHH- group). Mechanistically, the RGERDHH- group showed reduced lower esophageal sphincter basal pressure (P = 0.010) and EGJ contractile integral (P = 0.005). Notably, following a wet-swallow, the RGERDHH- group experienced the significant elevation in gastric pressure and TPG. Correlation analyses revealed weakly acidic reflux and bolus exposure were positively correlated with gastric pressure variation, and inversely correlated with lower esophageal sphincter basal pressure. Conclusions Transient gastric pressure elevation and compromised EGJ barrier function drive weakly acidic reflux and esophageal bolus exposure. This pressure gradient-barrier mismatch underpins the refractoriness of RGERD.

Acute kidney injury (AKI) is a prevalent and life-threatening clinical syndrome characterised by a rapid decline in renal function and diverse pathological etiologies. The condition has been demonstrated to be associated with elevated mortality rates and an increased risk of progression to chronic kidney disease. At present, clinicians depend heavily on conventional functional markers, such as serum creatinine and urine output, for the diagnosis and staging of the disease. It is evident that these conventional indicators characteristically manifest a considerable temporal delay and only undergo modification subsequent to considerable tissue damage. This severely restricts the timeframe for early detection and timely therapeutic intervention. Furthermore, standard markers fail to provide specific biological information regarding the underlying cellular injury mechanisms. The utilisation of advanced probe technologies in molecular imaging offers a robust alternative to overcome these inherent diagnostic limitations.This comprehensive review systematically evaluates recent progress in the design and application of two primary categories of molecular imaging tools for acute kidney disease, specifically reactive probes and enzyme-activated probes. Reactive probes are engineered to specifically interact with redox-active chemical species, including hydrogen peroxide, peroxynitrite, hypochlorous acid, and sulfur dioxide. Because oxidative stress constitutes a primary early event in acute renal tubular damage, these probes enable researchers and clinicians to visualize early cellular injury and radical accumulation well before global renal functional decline becomes evident. We discuss the application of these reactive probes across multiple imaging modalities including fluorescence imaging, magnetic resonance imaging (MRI), positron emission tomography (PET), and photoacoustic techniques. Photoacoustic imaging combines high spatial resolution with deep tissue penetration and has successfully demonstrated the ability to provide diagnostic alerts up to 12 h before any detectable rise in serum creatinine levels. Additionally, specific reactive probes have shown promising translational potential when tested by high-throughput screening in clinical human urine samples. Enzyme-activated probes target the specific catalytic activity of disease-relevant enzymes. These include well-documented renal tubular structural biomarkers such as NAG, GGT, and ALP, along with apoptosis-related caspases and specific nitroreductases. By responding only to enzymatic cleavage, these tools provide highly specific and pathology-directed imaging readouts. Recent structural design strategies in this field have advanced significantly beyond single-enzyme detection. Researchers are now focusing on sophisticated dual-target recognition to minimize background noise, multimodal integration to cross-validate imaging signals, and theranostic applications where probes simultaneously deliver diagnostic feedback and therapeutic agents to injured tissues. Nanotechnology serves as a fundamental enabler for realizing these advanced probe functions. By precisely optimizing nanoparticle parameters such as hydrodynamic size, surface charge, and targeting ligands, researchers can achieve amplified signal output, highly precise kidney delivery, and protection against premature degradation in the systemic circulation. For example, modifying surface charges can significantly enhance the active uptake of nanoprobes by damaged renal tubular epithelial cells.While preclinical probe development has progressed rapidly, moving these technologies into routine clinical practice remains a major challenge. We analyze the translational feasibility and current obstacles from biological, technological, and regulatory perspectives. Although biological targets such as KIM-1, FAP, and ALP have been validated in extensive patient cohorts, practical barriers severely limit their immediate clinical application. These obstacles involve complex changes in in vivo pharmacokinetics. During an acute injury episode, the extreme drop in the glomerular filtration rate alters probe clearance and can cause unwanted systemic accumulation or confusing background imaging signals. Other major hurdles include a lack of comprehensive long-term toxicity data and the absence of standardized manufacturing protocols to ensure batch-to-batch consistency. Future successful translation will require rigorous multi-center clinical studies to confirm the true diagnostic value of these probes over traditional markers. Researchers must also establish strict standardization of imaging procedures and comprehensive safety evaluations. Ultimately, this review provides a thorough reference framework for designing clinically translatable molecular probes and building a precision diagnostic imaging system for acute kidney injury.

Objective To investigate the relationship between quantitative parameters of the histogram of global fat fraction(FF)in the infrapatellar fat pad(IPFP)and the severity of knee osteoarthritis(KOA).Methods A total of 120 patients were prospectively selected and divided into the non-KOA group(KL grade 0-1),the mild KOA group(KL grade 2),and the severe KOA group(KL grade 3-4)based on the Kellgren-Lawrence(KL)classification criteria of knee X-rays.The FF maps of the IPFP were obtained based on the mDIXON-Quant technique.The region of interest(ROI)was delineated using 3D Slicer software,and global histogram analysis was performed to obtain quantitative parameters,including mean,median,10th percentile(10th),90th percentile(90th),skewness,kurtosis,and entropy.Pearson or Spearman correlation analysis was used to evaluate the correlation between each quanti-tative parameter and the severity of KOA.The diagnostic efficacy was analyzed using the receiver operating characteristic(ROC)curves.Results As the progression of KL classification,the mean,median,percentiles,and kurtosis of the global FF histogram quantitative parameters in the IPFP decreased,while skewness and entropy increased,with statistically significant among the three groups(P＜0.001).The mean,median,10th,90th,and kurtosis showed negative correlations with the KL classification(r=-0.563,-0.448,-0.614,-0.294,-0.450),while skewness and entropy showed positive correlations with the KL classification(r=0.385,0.637),all of which were statistically significant(P＜0.05).The area under the curve(AUC)for diagnosing KOA were 0.799,0.725,0.828,0.636,0.741,0.688,and 0.830,respectively.The sensitivity of the 10th and entropy were 74.4％and 77.9％,respectively,and the specificity were 85.3％and 88.2％,respectively.Conclusion The quantitative parameters of the histogram of global FF in the IPFP are correlated with the severity of KOA and can reflect the pathophysiological changes in the IPFP.They can serve as objective indicators for diagnosing KOA and assessing its severity.

Aim To investigate the mechanism by which sufentanil(Suf)improved hypoxia-reoxygen-ation(H/R)-induced myocardial cell injury by regula-ting hypoxia inducible factor-1α(HIF-1α)and KC-NQ1 opposite strand/antisense transcript 1(Kcnq1ot1).Methods Bioinformatics analysis was conducted to predict the interaction between HIF-1αand Kcnq1ot1.Subsequently,H9c2 cells were divided into multiple treatment groups:Ctrl group,H/R group,and Suf group.Further grouping was based on different transfection conditions,including oe-HIF-1α group,oe-HIF-1α+Suf group,sh-HIF-1α group,and sh-HIF-1α+Kcnq1ot1 group.Cell viability was detected u-sing the MTT assay,cell apoptosis was detected using the TUNEL assay,and the concentrations of CK-MB and HBDH in cell supernatants were measured using ELISA.HIF-1α protein expression in cellswas deter-mined by Western blot,and the mRNA expression level of Kcnq1ot1 was measured by reverse transcription quantitative PCR(RT-qPCR).Additionally,a rat model of myocardial is chemia reperfusion was con-structed to evaluate the therapeutic potential of Suf for myocardial ischemia reperfusion injury in vivo.Results The results of bioinformatics analysis showed a direct interaction between HIF-1α and Kcnq1ot1.Compared with the Ctrl group,the H/R group showed significantly reduced H9c2 cell viability,increased cell apoptosis,and significantly upregulated concentrations of CK-MB and HBDH,along with significantly enhanced expres-sion of HIF-1α and Kcnq1ot1(all P＜0.05).When H9c2 cells were transfected with oe-HIF-1 α,cell via-bility further decreased,apoptosis was worsened,and CK-MB and HBDH concentrations further increased(all P＜0.05);however,these adverse effects were significantly inhibited when combined with Suf inter-vention(all P＜0.05).Additionally,compared with the H/R group,the sh-HIF-1α group showed signifi-cantly improved cell viability,reduced apoptosis and decreased CK-MB and HBDH concentrations(all P＜0.05);however,these improvements were partially re-versed upon transfection with Kcnq1ot1(all P＜0.05).Animal experiments confirmed that Suf could improve myocardial ischemia-reperfusion injury in myo-cardial ischemia-reperfusion injury rats.Conclusions Suf improves myocardial H/R injury by inhibiting the HIF-1α-Kcnq1ot1.

Objective:To explore the application strategies and clinical effects of superior gluteal artery perforator tissue flaps in repairing stage Ⅳ pressure ulcers in the sacrococcygeal region.Methods:This study was a retrospective observational study. From July 2019 to April 2024, 89 patients with stage Ⅳ pressure ulcers in the sacrococcygeal region who met the inclusion criteria were admitted to the First Affiliated Hospital of Nanchang University, including 59 males and 30 females, aged 21 to 84 years. There were 89 sacrococcygeal pressure ulcers, with an area of 5.0 cm×4.0 cm-21.0 cm×21.0 cm after debridement. According to the shape, size, and depth of the wounds after debridement, combined with the elasticity and texture of the skin around the wounds, and the principle of minimizing damage to the donor area, the appropriate forms of superior gluteal artery perforator tissue flaps were cut for wound repair in the following three conditions. (1) For wounds with a round shape, an area of 5.0 cm×5.0 cm-21.0 cm×21.0 cm, and a depth of 1.0-3.5 cm, the superior gluteal artery perforator propeller flap or myocutaneous flap, bilobed superior gluteal artery perforator relay flap, and bilateral superior gluteal artery perforator rotational flap were used. (2) For wounds with an oval shape, an area of 5.0 cm×4.0 cm-18.5 cm×10.5 cm, and a depth of 1.0-3.0 cm, the superior gluteal artery perforator propeller flap or myocutaneous flap, unilateral superior gluteal artery perforator propeller flap combined with contralateral superior gluteal artery perforator V-Y advanced flap or keystone flap were used. (3) For wounds with a fusiformis shape, an area of 7.0 cm×4.0 cm-17.5 cm×6.0 cm, and a depth of 1.5-5.0 cm, the unilateral or bilateral superior gluteal artery perforator V-Y advanced flap, superior gluteal artery perforator keystone flap, or superior gluteal artery perforator keystone flap combined with gluteus maximus muscle flap were used. In this group of patients, a total of 40 superior gluteal artery perforator propeller flaps (with an resection area of 11.0 cm×6.0 cm-17.0 cm×11.0 cm), 22 superior gluteal artery perforator propeller myocutaneous flaps (with an resection area of 10.0 cm×5.0 cm-14.0 cm×8.0 cm), 7 bilobed superior gluteal artery perforator relay flaps (with a main flap resection area of 5.5 cm×5.5 cm-18.0 cm×11.5 cm and a side flap resection area of 4.5 cm×3.0 cm-11.0 cm×6.5 cm), 5 bilateral superior gluteal artery perforator rotational flaps (with a total resection area of 20.0 cm×16.0 cm-26.0 cm×21.0 cm on both sides), 14 superior gluteal artery perforator V-Y advanced flaps (with an resection area of 12.0 cm×10.0 cm-18.0 cm×18.0 cm), 13 superior gluteal artery perforator keystone flaps (with an resection area of 13.0 cm×6.5 cm-19.0 cm×18.0 cm), and 3 gluteus maximus muscle flaps (with an resection area of 8.0 cm×3.0 cm-15.0 cm×4.5 cm). The donor area wounds were all directly sutured. The survival of tissue flaps was observed and the incidence rate of delayed wound healing in the reception area was calculated, and wound healing in the donor area was observed. The appearance and texture of tissue flaps and recurrence of pressure ulcers were followed up.Results:After surgery, all bilateral superior gluteal artery perforator rotational flaps, superior gluteal artery perforator V-Y advanced flaps, superior gluteal artery perforator keystone flaps, and gluteus maximus muscle flaps survived well. There were 6 cases of delayed wound healing in the reception area after surgery, with an incidence rate of 6.7% (6/89). Two patients had incision dehiscence in the donor area wounds due to postoperative bleeding, the wounds healed after debridement, vacuum sealing drainage, and dressing change. The wounds in the donor area of the remaining patients healed well. Six patients were lost to follow-up. Eighty-three patients were followed up for 3-48 months, of whom 4 patients died. Among the remaining 79 patients, 3 cases had pressure ulcers recur due to improper nursing, while the rest of the patients had tissue flaps with good appearance and soft texture and no recurrence of pressure ulcers.Conclusions:Based on the characteristics of wound shape, size, and depth after debridement of stage Ⅳ pressure ulcers in the sacrococcygeal region, individualized selection of flap, myocutaneous flap, or a combination of flap and gluteus maximus muscle flap based on the perforating branch of the superior gluteal artery perforator can achieve good clinical repair results. The postoperative tissue flap survived well, with a good appearance, soft texture, and less recurrence of pressure ulcers.

Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91％of the total clinical isolates and 4.07％of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89％were isolated from children and 33.11％were isolated from adults.More than 90％of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79％in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06％were isolated from children and 19.94％isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0％.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.

Aim To investigate the mechanism by which sufentanil(Suf)improved hypoxia-reoxygen-ation(H/R)-induced myocardial cell injury by regula-ting hypoxia inducible factor-1α(HIF-1α)and KC-NQ1 opposite strand/antisense transcript 1(Kcnq1ot1).Methods Bioinformatics analysis was conducted to predict the interaction between HIF-1αand Kcnq1ot1.Subsequently,H9c2 cells were divided into multiple treatment groups:Ctrl group,H/R group,and Suf group.Further grouping was based on different transfection conditions,including oe-HIF-1α group,oe-HIF-1α+Suf group,sh-HIF-1α group,and sh-HIF-1α+Kcnq1ot1 group.Cell viability was detected u-sing the MTT assay,cell apoptosis was detected using the TUNEL assay,and the concentrations of CK-MB and HBDH in cell supernatants were measured using ELISA.HIF-1α protein expression in cellswas deter-mined by Western blot,and the mRNA expression level of Kcnq1ot1 was measured by reverse transcription quantitative PCR(RT-qPCR).Additionally,a rat model of myocardial is chemia reperfusion was con-structed to evaluate the therapeutic potential of Suf for myocardial ischemia reperfusion injury in vivo.Results The results of bioinformatics analysis showed a direct interaction between HIF-1α and Kcnq1ot1.Compared with the Ctrl group,the H/R group showed significantly reduced H9c2 cell viability,increased cell apoptosis,and significantly upregulated concentrations of CK-MB and HBDH,along with significantly enhanced expres-sion of HIF-1α and Kcnq1ot1(all P＜0.05).When H9c2 cells were transfected with oe-HIF-1 α,cell via-bility further decreased,apoptosis was worsened,and CK-MB and HBDH concentrations further increased(all P＜0.05);however,these adverse effects were significantly inhibited when combined with Suf inter-vention(all P＜0.05).Additionally,compared with the H/R group,the sh-HIF-1α group showed signifi-cantly improved cell viability,reduced apoptosis and decreased CK-MB and HBDH concentrations(all P＜0.05);however,these improvements were partially re-versed upon transfection with Kcnq1ot1(all P＜0.05).Animal experiments confirmed that Suf could improve myocardial ischemia-reperfusion injury in myo-cardial ischemia-reperfusion injury rats.Conclusions Suf improves myocardial H/R injury by inhibiting the HIF-1α-Kcnq1ot1.

Objective:To establish a quantitative analysis of multi-components by single marker(QAMS)for the determination of 6 alkaloid components,which is benzoylmesaconine,benzoyl-hypaconine,benzoylaconine,mesaconitine,hypaconitine,and aconitine in Zhachong Shisanwei Pills,and prove the scientificity and feasibility of the method in the quality analysis.Methods:The chromatographic separation was performed on an Agilent Eclipse Plus C18(250 mm×4.6 mm,5 μm)with gradient elution using 0.1 mol·L-1 ammonium acetate(0.5 mL of gla-cial acetic acid per 1 000 mL)(A)-acetonitrile:tetrahydrofuran(25∶15)(B),as the mobile phase(0-50 min,18%B-28%B),the detection wavelength was switched from 235 nm,the column temperature was kept at 40℃and the flow rate was 1.0 mL·min-1.The relative correction factors(fs/i)were established with the other 5 compo-nents to be measured using benzoylaconine as the internal reference,which were used to calculate the mass fraction of each component.At the same time,the mass fractions of the 6 effective constituents in Zhachong Shisanwei Pills were calculated by the external standard method(ESM).By comparing the content results of ESMand QAMS,the accura-cy of QAMS method were evaluated.Results:The relative correction factors(fs/i)of benzoylmesaconine,benzoylhyp-aconine,mesaconitine,hypaconitine,and aconitine in Mongolian medicine Zhachong Shisanwei Pills were reproduci-ble with good reproducibility,which were 0.680 4,0.450 6,0.850 8,0.676 1 and 0.757 0,the result obtained by QAMS approximated those obtained by external standard method(ESM).Conclusion:The method is simple,stable and reproducible,and can be used for the quality control of 6 alkaloid components in Zhachong Shisanwei Pills.

Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91％of the total clinical isolates and 4.07％of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89％were isolated from children and 33.11％were isolated from adults.More than 90％of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79％in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06％were isolated from children and 19.94％isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0％.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.

Objective:To explore the safety and efficacy of intraosseous regional administration (IORA) of vancomycin for preventing infection in primary total knee arthroplasty (TKA).Methods:A total of 124 patients with knee osteoarthritis undergoing TKA between February 2024 and May 2024 at nine hospitals were enrolled. Preoperative infection prophylaxis involved either IORA (0.5 g vancomycin administered via intraosseous regional infusion before incision) or intravenous infusion (1 g vancomycin via peripheral vein). The IORA group included 15 males and 47 females with a median age of 66.5 years (range, 60.0-70.0 years), while the intravenous group included 14 males and 48 females with a median age of 66.0 years (range, 61.8-70.3 years) years. Intraoperative samples were collected including fat and synovium tissues after incision, before prosthesis placement, and after tourniquet release; distal femoral cancellous bone during femoral osteotomy; proximal tibial cancellous bone during tibial osteotomy; proximal intercondylar cancellous bone before prosthesis placement; and peripheral blood from non-infused arms at surgery initiation and after tourniquet release. Vancomycin concentrations were measured using liquid chromatography-tandem mass spectrometry. Vital sign changes were recorded from admission to 5~10 minutes post-IORA (IORA group) or post-incision (intravenous group). Follow-ups were conducted on postoperative day 1 and 3, and at 1 and 3 months, to document complications including IORA-related adverse events, periprosthetic joint infections, surgical site infections, red man syndrome, acute kidney injury, deep vein thrombosis and so on.Results:Vancomycin concentrations in bone, fat, and synovial tissue samples were significantly higher in the IORA group than in the intravenous group ( P<0.05), while vancomycin concentrations in blood samples were significantly lower in the IORA group than in the intravenous group ( P<0.05). Only 7.3%(41/558) of tissue samples in the IORA group had vancomycin concentrations below 2.0 μg/g (the minimum inhibitory concentration of vancomycin against coagulase-negative staphylococcus), compared to 59.3%(331/558) in the intravenous group (χ 2=11.285, P<0.001). In the intravenous group, 16.9%(21/124) of blood samples had vancomycin concentrations exceeding 15.0 mg/L (the threshold associated with a significantly increased risk of nephrotoxicity), while all concentrations in the IORA group were below this threshold, the difference was statistically significant (χ 2=22.943, P<0.001). There were no statistically significant difference ( P>0.05) in vital signs changes before and after vancomycin administration between the two groups. Two patients in the intravenous group experienced incision exudate, while no other related complications occurred in either group. Conclusions:Compared to the traditional intravenous infusion of 1 g vancomycin, intraosseous injection of a low dose (0.5 g) of vancomycin achieves higher local tissue concentrations in the knee joint with a lower incidence of adverse reactions and is safe for infection prophylaxis. Despite guidelines not recommending the routine use of vancomycin for preventing infection after primary TKA, intraosseous injection of 0.5 g vancomycin may be considered intraoperatively for primary TKA in the following scenarios: patients in medical institutions with a high prevalence of methicillin-resistant staphylococcus aureus (MRSA) infections, patients with potential preoperative MRSA colonization, or patients with cephalosporin allergy.