Effects of palm olein and palm stearin on cecal and fecal microbiota of C57BL/6J mice under low and high fat intakes.

This work aimed to study the effects of dietary lipid composition and content on cecal and fecal microbiota of mice fed the following diets for 8 weeks: palm olein (PO)-based low-fat diet, PO-based high-fat diet, palm stearin (PS)-based low-fat diet, and PS-based high-fat diet. Increasing the dietary PS level favored the growth of Firmicutes over Bacteroidetes in the cecum and feces. In addition, it significantly elevated the total lipid (p < 0.01) and bile acid content (p < 0.01) in feces, resulting in the enrichment of fat-degrading and bile-acid tolerant genera within the families Ruminococcaceae and Lachnospiraceae. Although increasing the PO intake also caused obesity in mice, it did not affect the microbial structure. When fat intake is constant, only at a high-fat level can PS (vs PO) induce the above-mentioned microbial shifts. These results highlighted the combined roles of lipid quality and quantity on the gut microbiota.

Intraoperative Tobramycin Powder Prevents Enterobacter cloacae Surgical Site Infections in a Rabbit Model of Internal Fixation.

OBJECTIVES: To evaluate the efficacy of intraoperative tobramycin powder in preventing surgical site infection (SSI) and implant colonization with Enterobacter cloacae in a rabbit fixation model. Gram-negative rods, particularly Enterobacter species, comprise an increasing percentage of SSI at our institution. METHODS: Eighteen New Zealand White rabbits underwent surgical fixation of the left tibia with implantation of a plate and screws. The surgical site and implant were inoculated with 1 × 107 CFUs E. cloacae. The selected E. cloacae isolate was resistant to tobramycin and capable of forming biofilms. Nine rabbits received 125 mg tobramycin powder directly into the surgical site, overlying the implant. The control group was untreated. Fourteen days postinfection, the tibiae and implants were explanted. Radiographs were taken with and without the implants in place. One tibia from each group was examined after hematoxylin and eosin staining. The remaining tibiae and implants were morselized or sonicated, respectively, and plated on agar to determine infection burden. Data were analyzed with Fisher exact tests and Mann-Whitney U tests. RESULTS: No bone infection or implant colonization occurred in the tobramycin-treated group. In the control group, 7 of 8 rabbits developed bone infections (P = 0.001), and 4 of 8 implants were colonized (P = 0.07). No gross disruption of the normal bone architecture was observed in either group. CONCLUSIONS: Intraoperative tobramycin powder applied at the time of contamination prevented bone infection with E. cloacae in this rabbit fixation model. The results are encouraging because the E. cloacae isolate was tobramycin-resistant, demonstrating the utility of intraoperative powdered antibiotics.

The Efficacy of Breast Implant Irrigant Solutions: A Comparative Analysis Using an In Vitro Model.

BACKGROUND: Infections are challenging complications of implant-based breast reconstruction and augmentation. They pose a clinical challenge, with significant economic implications. One proposed solution is implant irrigation at the time of placement. There is no consensus on the optimal irrigant solution. METHODS: The authors tested the relative efficacy of 10% povidone-iodine, Clorpactin, Prontosan, triple-antibiotic solution, or normal saline (negative control) against two strains each of methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis. Sterile, smooth silicone implant disks were immersed in irrigant solution, then incubated in suspensions of methicillin-resistant S. aureus or S. epidermidis overnight. The disks were rinsed and sonicated to displace adherent bacteria from the implant surface, and the displaced bacteria were quantified. Normalized values were calculated to characterize the relative efficacy of each irrigant. RESULTS: Povidone-iodine resulted in reductions of the bacterial load by a factor of 10 to 10 for all strains. Prontosan-treated smooth breast implant disks had a 10-fold reduction in bacterial counts for all but one methicillin-resistant S. aureus strain. In comparison to Prontosan, triple-antibiotic solution demonstrated a trend of greater reduction in methicillin-resistant S. aureus bacterial load and weaker activity against S. epidermidis strains. Clorpactin reduced the recovered colony-forming units for only a single strain of S. epidermidis. Povidone-iodine demonstrated the greatest efficacy against all four strains. However, Clorpactin, triple-antibiotic solution, and Prontosan demonstrated similar efficacies. CONCLUSIONS: Povidone-iodine was the most efficacious of the irrigants at reducing methicillin-resistant S. aureus and S. epidermidis contamination. Given the recent lifting of the U.S. Food and Drug Administration moratorium, larger clinical studies of povidone-iodine as a breast implant irrigant solution are warranted. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, V.

The Arginine Deiminase Pathway Impacts Antibiotic Tolerance during Biofilm-Mediated Streptococcus pyogenes Infections.

Bacterial biofilms are responsible for a variety of serious human infections and are notoriously difficult to treat due to their recalcitrance to antibiotics. Further work is necessary to elicit a full understanding of the mechanism of this antibiotic tolerance. The arginine deiminase (ADI) pathway is responsible for bacterial pH maintenance and is highly expressed during biofilm growth in multiple bacterial species. Using the group A Streptococcus (GAS) as a model human pathogen, the ADI pathway was demonstrated to contribute to biofilm growth. The inability of antibiotics to reduce GAS populations when in a biofilm was demonstrated by in vitro studies and a novel animal model of nasopharyngeal infection. However, disruption of the ADI pathway returned GAS biofilms to planktonic levels of antibiotic sensitivity, suggesting the ADI pathway is influential in biofilm-related antibiotic treatment failure and provides a new strategic target for the treatment of biofilm infections in GAS and potentially numerous other bacterial species.IMPORTANCE Biofilm-mediated bacterial infections are a major threat to human health because of their recalcitrance to antibiotic treatment. Through the study of Streptococcus pyogenes, a significant human pathogen that is known to form antibiotic-tolerant biofilms, we demonstrated the role that a bacterial pathway known for responding to acid stress plays in biofilm growth and antibiotic tolerance. This not only provides some insight into antibiotic treatment failure in S. pyogenes infections but also, given the widespread nature of this pathway, provides a potentially broad target for antibiofilm therapies. This discovery has the potential to impact the treatment of many different types of recalcitrant biofilm infections.

Scnn1b-Transgenic BALB/c Mice as a Model of Pseudomonas aeruginosa Infections of the Cystic Fibrosis Lung.

The opportunistic pathogen Pseudomonas aeruginosa is responsible for much of the morbidity and mortality associated with cystic fibrosis (CF), a condition that predisposes patients to chronic lung infections. P. aeruginosa lung infections are difficult to treat because P. aeruginosa adapts to the CF lung, can develop multidrug resistance, and can form biofilms. Despite the clinical significance of P. aeruginosa, modeling P. aeruginosa infections in CF has been challenging. Here, we characterize Scnn1b-transgenic (Tg) BALB/c mice as P. aeruginosa lung infection models. Scnn1b-Tg mice overexpress the epithelial Na+ channel (ENaC) in their lungs, driving increased sodium absorption that causes lung pathology similar to CF. We intranasally infected Scnn1b-Tg mice and wild-type littermates with the laboratory P. aeruginosa strain PAO1 and CF clinical isolates and then assessed differences in bacterial clearance, cytokine responses, and histological features up to 12 days postinfection. Scnn1b-Tg mice carried higher bacterial burdens when infected with biofilm-grown rather than planktonic PAO1; Scnn1b-Tg mice also cleared infections more slowly than their wild-type littermates. Infection with PAO1 elicited significant increases in proinflammatory and Th17-linked cytokines on day 3. Scnn1b-Tg mice infected with nonmucoid early CF isolates maintained bacterial burdens and mounted immune responses similar to those of PAO1-infected Scnn1b-Tg mice. In contrast, Scnn1b-Tg mice infected with a mucoid CF isolate carried high bacterial burdens, produced significantly more interleukin 1ß (IL-1ß), IL-13, IL-17, IL-22, and KC, and showed severe immune cell infiltration into the bronchioles. Taken together, these results show the promise of Scnn1b-Tg mice as models of early P. aeruginosa colonization in the CF lung.

In Vitro Gastrointestinal Digestion of Palm Olein and Palm Stearin-in-Water Emulsions with Different Physical States and Fat Contents.

The impacts of lipid physical state and content on lipid digestion behavior were investigated using 4 and 20% palm olein-in-water emulsions (4% PO and 20% PO) and 4 and 20% palm stearin-in-water emulsions (4% PS and 20% PS). The changes of lipid physical state, particle size, and microstructure during gastrointestinal digestion; the free fatty acid (FFA) released in the intestinal phase; and the fatty acid composition of micellar phases were investigated. After gastric digestion, all emulsions underwent flocculation and coalescence, with 20% PS showing the most extensive aggregation. During intestinal digestion, the FFA release rate and level decreased as the lipid content increased from 4 to 20%, with 4% PO presenting the highest digestion rate and extent. Besides, the solid fat in 4% PS and 20% PS decreased and increased the maximum lipid digestibility, respectively. These results highlighted the combined roles of lipid physical state and content in modulating dietary lipid digestion.

Development of a Novel and Rapid Antibody-Based Diagnostic for Chronic Staphylococcus aureus Infections Based on Biofilm Antigens.

Prosthetic joint infections are difficult to diagnose and treat due to biofilm formation by the causative pathogens. Pathogen identification relies on microbial culture that requires days to weeks, and in the case of chronic biofilm infections, lacks sensitivity. Diagnosis of infection is often delayed past the point of effective treatment such that only the removal of the implant is curative. Early diagnosis of an infection based on antibody detection might lead to less invasive, early interventions. Our study examined antibody-based assays against the Staphylococcus aureus biofilm-upregulated antigens SAOCOL0486 (a lipoprotein), glucosaminidase (a domain of SACOL1062), and SACOL0688 (the manganese transporter MntC) for detection of chronic S. aureus infection. We evaluated these antigens by enzyme-linked immunosorbent assay (ELISA) using sera from naive rabbits and rabbits with S. aureus-mediated osteomyelitis, and then we validated a proof of concept for the lateral flow assay (LFA). The SACOL0688 LFA demonstrated 100% specificity and 100% sensitivity. We demonstrated the clinical diagnostic utility of the SACOL0688 antigen using synovial fluid (SF) from humans with orthopedic implant infections. Elevated antibody levels to SACOL0688 in clinical SF specimens correlated with 91% sensitivity and 100% specificity for the diagnosis of S. aureus infection by ELISA. We found measuring antibodies levels to SACOL0688 in SF using ELISA or LFA provides a tool for the sensitive and specific diagnosis of S. aureus prosthetic joint infection. Development of the LFA diagnostic modality is a desirable, cost-effective option, potentially providing rapid readout in minutes for chronic biofilm infections.

Minimum information guideline for spectrophotometric and fluorometric methods to assess biofilm formation in microplates.

The lack of reproducibility of published studies is one of the major issues facing the scientific community, and the field of biofilm microbiology has been no exception. One effective strategy against this multifaceted problem is the use of minimum information guidelines. This strategy provides a guide for authors and reviewers on the necessary information that a manuscript should include for the experiments in a study to be clearly interpreted and independently reproduced. As a result of several discussions between international groups working in the area of biofilms, we present a guideline for the spectrophotometric and fluorometric assessment of biofilm formation in microplates. This guideline has been divided into 5 main sections, each presenting a comprehensive set of recommendations. The intention of the minimum information guideline is to improve the quality of scientific communication that will augment interlaboratory reproducibility in biofilm microplate assays.

Clearance of Staphylococcus aureus from In Vivo Models of Chronic Infection by Immunization Requires Both Planktonic and Biofilm Antigens.

Staphylococcus aureus is a causative agent of chronic biofilm-associated infections that are recalcitrant to resolution by the immune system or antibiotics. To combat these infections, an antistaphylococcal, biofilm-specific quadrivalent vaccine against an osteomyelitis model in rabbits has previously been developed and shown to be effective at eliminating biofilm-embedded bacterial populations. However, the addition of antibiotics was required to eradicate remaining planktonic populations. In this study, a planktonic upregulated antigen was combined with the quadrivalent vaccine to remove the need for antibiotic therapy. Immunization with this pentavalent vaccine followed by intraperitoneal challenge of BALB/c mice with S. aureus resulted in 16.7% and 91.7% mortality in pentavalent vaccine and control groups, respectively (P < 0.001). Complete bacterial elimination was found in 66.7% of the pentavalent cohort, while only 8.3% of the control animals cleared the infection (P < 0.05). Further protective efficacy was observed in immunized rabbits following intramedullary challenge with S. aureus, where 62.5% of the pentavalent cohort completely cleared the infection, versus none of the control animals (P < 0.05). Passive immunization of BALB/c mice with serum IgG against the vaccine antigens prior to intraperitoneal challenge with S. aureus prevented mortality in 100% of mice and eliminated bacteria in 33.3% of the challenged mice. These results demonstrate that targeting both the planktonic and biofilm stages with the pentavalent vaccine or the IgG elicited by immunization can effectively protect against S. aureus infection.

The Host Immune System Facilitates Disseminated Staphylococcus aureus Disease Due to Phagocytic Attraction to Candida albicans during Coinfection: a Case of Bait and Switch.

Invasive Staphylococcus aureus infections account for 15 to 50% of fatal bloodstream infections annually. These disseminated infections often arise without a defined portal of entry into the host but cause high rates of mortality. The fungus Candida albicans and the Gram-positive bacterium S. aureus can form polymicrobial biofilms on epithelial tissue, facilitated by the C. albicans adhesin encoded by ALS3 While a bacterium-fungus interaction is required for systemic infection, the mechanism by which bacteria disseminate from the epithelium to internal organs is unclear. In this study, we show that highly immunogenic C. albicans hyphae attract phagocytic cells, which rapidly engulf adherent S. aureus and subsequently migrate to cervical lymph nodes. Following S. aureus-loaded phagocyte translocation from the mucosal surface, S. aureus produces systemic disease with accompanying morbidity and mortality. Our results suggest a novel role for the host in facilitating a bacterium-fungus infectious synergy, leading to disseminated staphylococcal disease.

Inhibitory effects of two types of food additives on biofilm formation by foodborne pathogens.

The inhibition of microbial biofilms is a significant concern in food safety. In the present study, the inhibitory effect of sodium citrate and cinnamic aldehyde on biofilm formation at minimum inhibitory concentrations (MICs) and sub-MICs was investigated for Escherichia coli O157:H7 and Staphylococcus aureus. The biofilm inhibition rate was measured to evaluate the effect of sodium citrate on S. aureus biofilms at 24, 48, 72, and 96 hr. According to the results, an antibiofilm effect was shown by both food additives, with 10 mg/ml of sodium citrate exhibiting the greatest inhibition of S. aureus biofilms at 24 hr (inhibition rate as high as 77.51%). These findings strongly suggest that sodium citrate exhibits a pronounced inhibitory effect on biofilm formation with great potential in the extension of food preservation and storage.

Biofilm Formation of Staphylococcus aureus under Food Heat Processing Conditions: First Report on CML Production within Biofilm.

This study aimed to evaluate the Staphylococcus aureus biofilm formation and Nε-carboxymethyl-lysine generation ability under food heat processing conditions including pH (5.0-9.0), temperature (25 °C, 31 °C, 37 °C, 42 °C and 65 °C), NaCl concentration (10%, 15% and 20%, w/v) and glucose concentration (0.5%, 1%, 2%, 3%, 5%, 10%, w/v). S. aureus biofilm genetic character was obtained by PCR detecting atl, ica operon, sasG and agr. Biofilm biomass and metabolic activity were quantified with crystal violet and methyl thiazolyl tetrazolium staining methods. S. aureus biofilm was sensitive to food heat processing conditions with 37 °C, pH 7.0, 2% glucose concentration (w/v) and 10% NaCl concentration (w/v) were favorable conditions. Besides, free and bound Nε-carboxymethyl-lysine level in weak, moderate and strong biofilm were detected by optimized high performance liquid chromatography tandem mass spectrometry. Nε-carboxymethyl-lysine level in S. aureus biofilm possessed a significant gap between strong, moderate and weak biofilm strains. This investigation revealed the biological and chemical hazard of Staphylococcus aureus biofilm to food processing environment.

Temporal proteomic profiling reveals changes that support Burkholderia biofilms.

Melioidosis associated with opportunistic pathogen Burkholderia pseudomallei imparts a huge medical burden in Southeast Asia and Australia. At present there is no available human vaccine that protects against B. pseudomallei infection and antibiotic treatments are limited particularly for drug-resistant strains and bacteria in biofilm forms. Biofilm forming bacteria exhibit phenotypic features drastically different to their planktonic states, often exhibiting a diminished response to antimicrobial therapies. Our earlier work on global profiling of bacterial biofilms using transcriptomics and proteomics revealed transcript-decoupled protein abundance in bacterial biofilms. Here we employed reverse phase liquid chromatography tandem mass spectrometry (LC-MS/MS) to deduce temporal proteomic differences in planktonic and biofilm forms of Burkholderia thailandensis, which is weakly surrogate model of pathogenic B. pseudomallei as sharing a key element in genomic similarity. The proteomic analysis of B. thailandensis in biofilm versus planktonic states revealed that proteome changes support biofilm survival through decreased abundance of metabolic proteins while increased abundance of stress-related proteins. Interestingly, the protein abundance including for the transcription protein TEX, outer periplasmic TolB protein, and the exopolyphosphatase reveal adaption in bacterial biofilms that facilitate antibiotic tolerance through a non-specific mechanism. The present proteomics study of B. thailandensis biofilms provides a global snapshot of protein abundance differences and antimicrobial sensitivities in planktonic and sessile bacteria.

Complete Sequence of a Novel Multidrug-Resistant Pseudomonas putida Strain Carrying Two Copies of qnrVC6.

This study aimed at identification and characterization of a novel multidrug-resistant Pseudomonas putida strain Guangzhou-Ppu420 carrying two copies of qnrVC6 isolated from a hospital in Guangzhou, China, in 2012. Antimicrobial susceptibility was tested by Vitek2™ Automated Susceptibility System and Etest™ strips, and whole-genome sequencing facilitated analysis of its multidrug resistance. The genome has a length of 6,031,212 bp and an average G + C content of 62.01%. A total of 5,421 open reading frames were identified, including eight 5S rRNA, seven 16S rRNA, and seven 23S rRNA, and 76 tRNA genes. Importantly, two copies of qnrVC6 gene with three ISCR1 around, a blaVIM-2 carrying integron In528, a novel gcu173 carrying integron In1348, and six antibiotic resistance genes were identified. This is the first identification of two copies of the qnrVC6 gene in a single P. putida isolate and a class 1 integron In1348.

Transcriptomics Study on Staphylococcus aureus Biofilm Under Low Concentration of Ampicillin.

Staphylococcus aureus is one of the representative foodborne pathogens which forms biofilm. Antibiotics are widely applied in livestock husbandry to maintain animal health and productivity, thus contribute to the dissemination of antimicrobial resistant livestock and human pathogens, and pose a significant public health threat. Effect of antibiotic pressure on S. aureus biofilm formation, as well as the mechanism, remains unclear. In this study, the regulatory mechanism of low concentration of ampicillin on S. aureus biofilm formation was elucidated. The viability and biomass of biofilm with and without 1/4 MIC ampicillin treatment for 8 h were determined by XTT and crystal violet straining assays, respectively. Transcriptomics analysis on ampicillin-induced and non-ampicillin-induced biofilms were performed by RNA-sequencing, differentially expressed genes identification and annotation, GO functional and KEGG pathway enrichment. The viability and biomass of ampicillin-induced biofilm showed dramatical increase compared to the non-ampicillin-induced biofilm. A total of 530 differentially expressed genes (DEGs) with 167 and 363 genes showing up- and down-regulation, respectively, were obtained. Upon GO functional enrichment, 183, 252, and 21 specific GO terms in biological process, molecular function and cellular component were identified, respectively. Eight KEGG pathways including "Microbial metabolism in diverse environments", "S. aureus infection", and "Monobactam biosynthesis" were significantly enriched. In addition, "beta-lactam resistance" pathway was also highly enriched. In ampicillin-induced biofilm, the significant up-regulation of genes encoding multidrug resistance efflux pump AbcA, penicillin binding proteins PBP1, PBP1a/2, and PBP3, and antimicrobial resistance proteins VraF, VraG, Dlt, and Aur indicated the positive response of S. aureus to ampicillin. The up-regulation of genes encoding surface proteins ClfB, IsdA, and SasG and genes (cap5B and cap5C) which promote the adhesion of S. aureus in ampicillin induced biofilm might explain the enhanced biofilm viability and biomass.

Microbial virulence, molecular epidemiology and pathogenic factors of fluoroquinolone-resistant Haemophilus influenzae infections in Guangzhou, China.

BACKGROUND: Fluoroquinolone-resistant Haemophilus influenzae (FRHI) has been reported worldwide but remain unclear in China. METHODS: A total of 402 H. influenzae isolates collected from 2016 to 2017 were included. Antimicrobial susceptibility on 10 antibiotics was performed, and minimum inhibitory concentration of ciprofloxacin- and nalidixic acid-resistant strains were further determined by E-test strips, with risk factors also evaluated. Strains with resistance or reduced susceptibility to ciprofloxacin were subjected to sequencing of the quinolone resistance-determining regions (QRDR) and plasmid-mediated quinolone resistance genes by sequencing, with multi-locus sequence typing. RESULTS: 2.2% of H. influenzae strains were non-susceptible (7/402, 1.7%) or susceptible (2/402, 0.5%) to ciprofloxacin but NAL-resistant by E-test, and multidrug resistance was more common in fluoroquinolones non-susceptible H. influenzae group (p = 0.000). Infection risk factors included invasive procedure (p = 0.011), catching cold/previous contact with someone who had a cold (p = 0.019), fluoroquinolones use during previous 3 months (p = 0.003). With none of mutations obtained in gyrB, parE and other plasmid-mediated quinolone resistance genes, 7 and 4 strains were found for Ser-84-Leu substitutions in gyrA and one amino acid substitution in the QRDR of gyrA linked with one amino acid substitution in the QRDR of parC, respectively. In addition, five sequence types (ST) were identified, with ST1719 firstly found. CONCLUSIONS: For the first time, this study has reported the incidence, risk factors, molecular determinants on fluoroquinolones resistance and ST of FRHI strains in mainland China, representing the first evidence of mutation of gyrA and parC in China and the new ST1719 worldwide.

Induction and Recovery of the Viable but Nonculturable State of Hop-Resistance Lactobacillus brevis.

Lactobacillus brevis is a major hop-resistance bacterium which poses significant challenge for the brewing industry, mainly due to the difficulty or incapability in detection by routine culturing methodology and its beer spoilage ability.This study aimed at investigating the VBNC state of a hop-resistance strain, L. brevis BM-LB13908. The culturable, total and viable numbers of L. brevis cells were calculated by MRS agar plate counting, acridine orange direct count (AODC) method and Live/Dead BacLight bacterial viability kit with fluorescence microscope. VBNC formation was induced by 189 ± 5.7 days under low-temperature storage or 27 ± 1.2 subcultures by continuous passage in beer, and VBNC cells induced by both strategies were recovered by adding catalase. In addition, insignificant difference in beer-spoilage ability was found in 3 states of L. brevis, including logarithmic growing, VBNC and recovered cells. This is the first study on the formation of VBNC state for L. brevis and beer-spoilage ability of both VBNC and recovered cells, which indicate L. brevis strain could cause beer spoilage without being detected by routine methodologies. The results derived from this study may support further study on L. brevis and other hop-resistance bacteria, and guidance on beer spoilage prevention and control, such as improvement for brewers on the microbiological quality control by using the improved culture method with catalase supplementation.

Variations in the Organisms Causing Deep Surgical Site Infections in Fracture Patients at a Level I Trauma Center (2006-2015).

OBJECTIVES: To quantify the current bacteriology of deep surgical site infections (SSIs) after fracture surgery at 1 institution and to compare those data with historical controls at the same institution, assessing variations in infecting organisms over the past decade. DESIGN: Retrospective review. SETTING: Level I trauma center. PATIENTS/PARTICIPANTS: Two hundred forty-three patients requiring surgical intervention for deep SSI between January 2011 and December 2015 were compared with 211 patients requiring surgical intervention for deep SSI between December 2006 and December 2010. INTERVENTION: None. MAIN OUTCOME MEASUREMENTS: Bacteria were categorized as Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus, Enterococcus, gram-negative rods (GNR), gram-positive rods, anaerobes, or negative cultures. The proportion of each bacterial type was determined and compared with previously published data from the same trauma center (December 2006 to December 2010). RESULTS: Patients most commonly had S. aureus infections (48%), followed by GNR (40%) and CoNS (19%). The proportion of CoNS species (26% vs. 12%, P < 0.01) in infected patients was significantly higher during the current study period compared with historical controls. The proportion of S. aureus species in infected patients was significantly less during the current study period (39% vs. 56%, P < 0.01). The reduction in the proportion of S. aureus species in infected patients was driven by a decrease in the proportion of methicillin-resistant S. aureus (MRSA) in the overall sample. CONCLUSIONS: Bacteriology of deep SSI of fractures has changed substantially over the past decade at our center, specifically the proportions of GNR, CoNS, and MRSA. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Discovery and control of culturable and viable but non-culturable cells of a distinctive Lactobacillus harbinensis strain from spoiled beer.

Occasional beer spoilage incidents caused by false-negative isolation of lactic acid bacteria (LAB) in the viable but non-culturable (VBNC) state, result in significant profit loss and pose a major concern in the brewing industry. In this study, both culturable and VBNC cells of an individual Lactobacillus harbinensis strain BM-LH14723 were identified in one spoiled beer sample by genome sequencing, with the induction and resuscitation of VBNC state for this strain further investigated. Formation of the VBNC state was triggered by low-temperature storage in beer (175 ± 1.4 days) and beer subculturing (25 ± 0.8 subcultures), respectively, and identified by both traditional staining method and PMA-PCR. Resuscitated cells from the VBNC state were obtained by addition of catalase rather than temperature upshift, changing medium concentration, and adding other chemicals, and both VBNC and resuscitated cells retained similar beer-spoilage capability as exponentially growing cells. In addition to the first identification of both culturable and VBNC cells of an individual L. harbinensis strain from spoiled beer, this study also for the first time reported the VBNC induction and resuscitation, as well as verification of beer-spoilage capability of VBNC and resuscitated cells for the L. harbinensis strain. Genes in association with VBNC state were also identified by the first genome sequencing of beer spoilage L. harbinensis. The results derived from this study suggested the contamination and spoilage of beer products by VBNC and resuscitated L. harbinensis strain BM-LH14723.