Attrition from Care Among Men Initiating ART in Male-Only Clinics Compared with Men in General Primary Healthcare Clinics in Khayelitsha, South Africa: A Matched Propensity Score Analysis.

Men have higher rates of attrition from antiretroviral therapy (ART) programs than women. In Khayelitsha, a high HIV prevalence area in South Africa, two public sector primary healthcare clinics offer services, including HIV testing and treatment, exclusively to men. We compared attrition from ART care among men initiating ART at these clinics with male attrition in six general primary healthcare clinics in Khayelitsha. We described baseline characteristics of patients initiating ART at the male and general clinics from 1 January 2014 to 31 March 2018. We used exposure propensity scores (generated based on baseline health and age) to match male clinic patients 1:1 to males at other clinics. The association between attrition (death or loss to follow-up, defined as no visits for nine months) and clinic type was estimated using Cox proportional hazards regression. Follow-up time began at ART initiation and ended at attrition, clinic transfer, or dataset closure. Before matching, patients from male clinics (n = 784) were younger than males from general clinics (n = 2726), median age: 31.2 vs 35.5 years. Those initiating at male clinics had higher median CD4 counts at ART initiation [Male Clinic 1: 329 (IQR 210-431), Male Clinic 2: 364 (IQR 260-536), general clinics 258 (IQR 145-398), cells/mm3]. In the matched analysis (1451 person-years, 1568 patients) patients initiating ART at male clinics had lower attrition (HR 0.71; 95% CI 0.60-0.85). In separate analyses for each of the two male clinics, only the more established male clinic showed a protective effect. Male-only clinics reached younger, healthier men, and had lower ART attrition than general services. These findings support clinic-specific adaptations to create more male-friendly environments.

Accuracy of a Smartwatch to Assess Heart Rate Monitoring and Atrial Fibrillation in Stroke Patients.

(1) Background: Consumer smartwatches may be a helpful tool to screen for atrial fibrillation (AF). However, validation studies on older stroke patients remain scarce. The aim of this pilot study from RCT NCT05565781 was to validate the resting heart rate (HR) measurement and the irregular rhythm notification (IRN) feature in stroke patients in sinus rhythm (SR) and AF. (2) Methods: Resting clinical HR measurements (every 5 min) were assessed using continuous bedside ECG monitoring (CEM) and the Fitbit Charge 5 (FC5). IRNs were gathered after at least 4 h of CEM. Lin's concordance correlation coefficient (CCC), Bland-Altman analysis, and mean absolute percentage error (MAPE) were used for agreement and accuracy assessment. (3) Results: In all, 526 individual pairs of measurements were obtained from 70 stroke patients-age 79.4 years (SD ± 10.2), 63% females, BMI 26.3 (IQ 22.2-30.5), and NIHSS score 8 (IQR 1.5-20). The agreement between the FC5 and CEM was good (CCC 0.791) when evaluating paired HR measurements in SR. Meanwhile, the FC5 provided weak agreement (CCC 0.211) and low accuracy (MAPE 16.48%) when compared to CEM recordings in AF. Regarding the accuracy of the IRN feature, analysis found a low sensitivity (34%) and high specificity (100%) for detecting AF. (4) Conclusion: The FC5 was accurate at assessing the HR during SR, but the accuracy during AF was poor. In contrast, the IRN feature was acceptable for guiding decisions regarding AF screening in stroke patients.

Galanin (1-15) Enhances the Behavioral Effects of Fluoxetine in the Olfactory Bulbectomy Rat, Suggesting a New Augmentation Strategy in Depression.

BACKGROUND: Selective serotonergic reuptake inhibitors, including fluoxetine (FLX), are the most commonly used for the treatment of major depression. However, they are effective for remission in only 30% of patients. Recently, we observed that Galanin (1-15) [GAL(1-15)] enhanced the antidepressant effects of FLX in naïve animals, suggesting a new augmentation strategy in depression. METHODS: We have analyzed in an animal model of depression, the olfactory bulbectomy (OBX) rats, the effect of GAL(1-15) on FLX-mediated responses in the forced swimming test and the sucrose preference test and the involvement of GAL receptor 2 with its antagonist, M871. We have also studied the corticosterone levels in OBX after the coadministration of GAL(1-15) with FLX. Moreover, we studied whether the effects of GAL(1-15) on FLX actions were mediated via auto- and heteroreceptor 5-HT1A (5-HT1AR), analyzing the binding characteristics, mRNA levels, and functionality of 5-HT1AR in the dorsal hippocampus. RESULTS: GAL(1-15) enhances the antidepressant-like effects induced by FLX in OBX animals in the forced swimming test and the sucrose preference test. The involvement of the GALR2 was demonstrated with M871. Importantly, the mechanism underlying the GAL(1-15)/FLX interactions in the OBX animals involves the 5-HT1AR in the hippocampus at the plasma membrane (increase of affinity and density of 5HT1AR in the DG) and transcriptional (increase of 5HT1AR mRNA levels in DG and CA1) levels. Besides, the coadministration of GAL(1-15) and FLX also reduced OBX-increased corticosterone levels. CONCLUSIONS: The results open the possibility to use GAL(1-15) in combination with FLX as a novel strategy for the treatment of depression.

Systemic Jak1 activation causes extrarenal calcitriol production and skeletal alterations provoking stunted growth.

Mineral homeostasis is regulated by a complex network involving endocrine actions by calcitriol, parathyroid hormone (PTH), and FGF23 on several organs including kidney, intestine, and bone. Alterations of mineral homeostasis are found in chronic kidney disease and other systemic disorders. The interplay between the immune system and the skeletal system is not fully understood, but cytokines play a major role in modulating calcitriol production and function. One of the main cellular signaling pathways mediating cytokine function is the Janus kinase (JAK)--signal transducer and activator of transcription (STAT) pathway. Here, we used a mouse model (Jak1S645P+/- ) that resembles a constitutive activating mutation of the Jak1/Stat3 signaling pathway in humans, and shows altered mineral metabolism, with higher fibroblast growth factor 23 (FGF23) levels, lower PTH levels, and higher calcitriol levels. The higher calcitriol levels are probably due to extrarenal calcitriol production. Furthermore, systemic Jak1/Stat3 activation led to growth impairment and skeletal alterations. The growth plate in long bones showed decreased chondrocyte proliferation rates and reduced height of terminal chondrocytes. Furthermore, we demonstrate that Jak1 is also involved in bone remodeling early in life. Jak1S645P+/- animals have decreased bone and cortical volume, imbalanced bone remodeling, reduced MAP kinase signaling, and local inflammation. In conclusion, Jak1 plays a major role in bone health probably both, directly and systemically by regulating mineral homeostasis. Understanding the role of this signaling pathway will contribute to a better knowledge in bone growth and in mineral physiology, and to the development of selective Jak inhibitors as osteoprotective agents.

HIV Self-testing Among Previously Diagnosed HIV-Positive People in Khayelitsha, South Africa: No Evidence of Harm but may Facilitate Re-engagement in ART Care.

In South Africa, where an estimated 34% of nearly 7-million HIV-positive people were not on antiretroviral therapy (ART) in 2019, innovative strategies to diagnose and link people to care are needed. HIV self-testing (HIVST) is one such strategy. However, there is concern that access to HIVST might result in re-testing among people on ART, with a risk of false negative results and disengagement from care. Between November 2017 and December 2018, HIVST kits were distributed at a private pharmacy and at HIV testing outreach events. Each participant was instructed to report their result via SMS and those who did not were followed-up telephonically 10 days later. Electronic medical records of participants were searched for evidence of HIV services 6 months before and after enrollment. Of 1482 participants, 163 (11%) were previously diagnosed HIV-positive prior to taking the test. Of these, 123 reported a result, however 87% reported a negative result. Of the 163 previously diagnosed, 84 were not in ART care prior to the test, with 15 (18%) linking to care post-test. Of 79 who were in ART care prior to the test, 76 (96%) remained in care, even though 51 (67%) had reported a negative result. Overall, 29% of participants reported their result via SMS, and 48% when telephoned. Despite efforts to dissuade them, some previously diagnosed HIV-positive utilised HIVST. For those disengaged from care this may facilitate re-engagement. Self-testing among those already in care, regardless of the reported result, did not disrupt their treatment, and their reasons for doing the test remain unclear.

Delivering PrEP to Young Women in a Low-Income Setting in South Africa: Lessons for Providing Both Convenience and Support.

Daily oral pre-exposure prophylaxis (PrEP) is a key tool in addressing high HIV incidence among young women, and breaking the cycle of transmission. From 2017 to 2020, Médecins Sans Frontières (MSF) offered PrEP, in conjunction with contraception and risk-reduction counselling, to women aged 18-25, in a government-run clinic in Khayelitsha, a low income high HIV prevalence area in South Africa. Drawing on clinical, quantitative, and qualitative interview data, we describe participants' experiences and engagement with the PrEP program, participant adherence (measured by TFV-DP levels in dried blood spots) over time, and the indirect benefits of the PrEP program. Of 224 screened and eligible participants, 164 (73.2%) initiated PrEP, with no large differences between those who initiated and those who did not. Overall, 47 (29%) completed 18 months follow-up, with 15 (9.1%) attending all visits. 76 (46.9%) participants were lost to follow-up, 15 (9.1%) exited when leaving the area, and 28.7% of exits happened in the first month of the study. We identified two different trajectories of PrEP adherence: 67% of participants had, on average, consistently low TFV-DP levels, with the remaining 33% having sustained high adherence. Few baseline characteristics predicted good adherence. The main reported barrier to taking PrEP was forgetting to take or travel with the pills. Encouragement from others declined as a reported facilitator from month 6 to 18 (family: 93.1% vs 77.6%, p = 0.016, friends: 77.6% vs 41.4%, p ≤ 0.001, partners: 62.1% vs 46.6%, p = 0.096, other PrEP users: 89.7% vs 74.1%, p = 0.020). Disclosure to friends and family in some cases opened dialogue around sex, and helped to educate others about PrEP. Self-reported sex with more than one partner, and sex without a condom, decreased significantly after enrolment (p < 0.001, p = 0.063). In the individual interviews, participants credited their PrEP experience with changing their behaviour. Recognising the challenges with, but overall benefits from a package of care that includes the option of PrEP, lessons drawn from this study can help maximise persistence on PrEP within resource constraints. PrEP providers need to address participants' need for both convenience and social support.

The Formation of the Epiphyseal Bone Plate Occurs via Combined Endochondral and Intramembranous-Like Ossification.

The formation of the epiphyseal bone plate, the flat bony structure that provides strength and firmness to the growth plate cartilage, was studied in the present study by using light, confocal, and scanning electron microscopy. Results obtained evidenced that this bone tissue is generated by the replacement of the lower portion of the epiphyseal cartilage. However, this process differs considerably from the usual bone tissue formation through endochondral ossification. Osteoblasts deposit bone matrix on remnants of mineralized cartilage matrix that serve as a scaffold, but also on non-mineralized cartilage surfaces and as well as within the perivascular space. These processes occur simultaneously at sites located close to each other, so that, a core of the sheet of bone is established very quickly. Subsequently, thickening and reshaping occurs by appositional growth to generate a dense parallel-fibered bone structurally intermediate between woven and lamellar bone. All these processes occur in close relationship with a cartilage but most of the bone tissue is generated in a manner that may be considered as intramembranous-like. Overall, the findings here reported provide for the first time an accurate description of the tissues and events involved in the formation of the epiphyseal bone plate and gives insight into the complex cellular events underlying bone formation at different sites on the skeleton.

Galanin(1-15) Potentiates the Antidepressant-like Effects Induced by Escitalopram in a Rat Model of Depression.

Selective 5-HT reuptake inhibitor antidepressants (SSRIs) are the first choice in major depressive disorder (MDD), but 50% of affected patients do not show improvement. Galanin(1-15) [GAL(1-15)] enhanced Fluoxetine antidepressant-like effects in an animal model of depression, the olfactory bulbectomy (OBX); however, further detailed analysis of GAL(1-15) effects as augmentation treatment in OBX rats are needed. In OBX rats, we analysed the effect of GAL(1-15) on Escitalopram (ESC)-mediated responses in behavioural tests related to despair. We studied whether GAL(1-15) effects involved 5-HT1AR using an in vivo model siRNA 5-HT1A knockdown rats. Moreover, we analysed by immunohistochemistry the expression of the immediate-early gene c-Fos (c-Fos IR) after the administration of GAL(1-15)+ESC in OBX rats in several nuclei involved in MDD. GAL(1-15) enhances the antidepressant-like effects of ESC, and the GALR2 antagonist M871 blocked GAL(1-15) mediated actions. The downregulation of 5-HT1AR by siRNA was sufficient to block GAL(1-15) effects. Our immunohistochemistry and principal component analysis (PCA) analysis suggest that two functional networks are involved in these effects; one includes the lateral (LHb) and medial (mHb) habenula, dorsal raphe (DR) and ventral tegmental area (VTA), and the other consists of the dentate gyrus (DG), and prefrontal cortex (PFC). The results open up the possibility of using GAL(1-15) in combination with SSRIs as a novel strategy for treating MDD.

Genome-wide search of nucleosome patterns using visual analytics.

MOTIVATION: The Burrows-Wheeler transform (BWT) is widely used for the fast alignment of high-throughput sequence data. This method also has potential applications in other areas of bioinformatics, and it can be specially useful for the fast searching of patterns on coverage data from different sources. RESULTS: We present a nucleosome pattern search method that converts levels of nucleosomal occupancy to a sequence-like format to which BWT searches can be applied. The method is embedded in a nucleosome map browser, 'Nucleosee', an interactive visual tool specifically designed to enhance BWT searches, giving them context and making them suitable for visual discourse analysis of the results. The proposed method is fast, flexible and sufficiently generic for the exploration of data in a broad and interactive way. AVAILABILITY AND IMPLEMENTATION: The proposed algorithm and visual browser are available for testing at http://cpg3.der.usal.es/nucleosee. The source code and installation packages are also available at https://github.com/rodrigoSantamaria/nucleosee. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

MAPK inhibition and growth hormone: a promising therapy in XLH.

X-linked hypophosphatemia (XLH) leads to growth retardation and bone deformities, which are not fully avoided by conventional treatment with phosphate and vitamin D analogs. Pediatric patients have been treated with growth hormone (GH), and recent findings suggest that blocking fibroblast growth factor 23 actions may be the most effective therapy, but its effects on growth are not known. We here report the effect of MAPK inhibition alone or associated with GH on growth and growth plate and bone structure of young Hyp (the XLH animal model) mice. Untreated Hyp mice were severely growth retarded and had marked alterations in both growth plate structure and dynamics as well as defective bone mineralization. GH accelerated growth and improved mineralization and the cortical bone, but it failed in normalizing growth plate and trabecular bone structures. MAPK inhibition improved growth and rickets and, notably, almost normalized the growth plate organization. The administration of a MAPK pathway inhibitor plus GH was the most beneficial treatment because of the positive synergistic effect on growth plate and bone structures. Thus, the growth-promoting effect of GH is likely linked to increased risk of bone deformities, whereas the association of GH and MAPK inhibition emerges as a promising new therapy for children with XLH.-Fuente, R., Gil-Peña, H., Claramunt-Taberner, D., Hernández-Frías, O., Fernández-Iglesias, Á., Alonso-Durán, L., Rodríguez-Rubio, E., Hermida-Prado, F., Anes-González, G., Rubio-Aliaga, I., Wagner, C., Santos, F. MAPK inhibition and growth hormone: a promising therapy in XLH.

Knowledge transmission, peer support, behaviour change and satisfaction in post Natal clubs in Khayelitsha, South Africa: a qualitative study.

BACKGROUND: The Post Natal Club (PNC) model assures comprehensive care, including HIV and Maternal and Child Health care, for postpartum women living with HIV and their infants during an 18-month postnatal period. The PNC model was launched in 2016 in Town Two Clinic, a primary health care facility in Khayelitsha, South Africa. This qualitative research study aims to understand how participation in PNCs affected knowledge transmission, peer support, behaviour change and satisfaction with the care provided. METHODS: We conducted ten in-depth interviews; three focus group discussions and participant observation with PNC members, health-care workers and key informants selected through purposive sampling. Seventeen PNC members between 21 and 38 years old, three key informants and seven staff working in PNC participated in the research. All participants were female, except for one of the three key informants who was male. Data was collected until saturation. The data analysis was performed in an inductive way and involved an iterative process, using Nvivo11 software. RESULTS: PNC members acquired knowledge on HIV, ART, adherence, infant feeding, healthy eating habits, follow up tests and treatment for exposed infants. Participants believed that PNC created strong relationships among members and offered an environment conducive to sharing experience and advice. Most interviewees stated that participating in PNC facilitated disclosure of their HIV status, enhanced support network and provided role models. PNC members said that they adapted their behaviour based on advice received in PNCs related to infant feeding, ART adherence, monitoring of symptoms and stimulation of early childhood development. The main benefits were believed to be comprehensive care for mother-infant pairs, time-saving and the peer dynamic. The main challenge from the perspective of key informants was the sustainability of dedicating human resources to PNC. CONCLUSION: The PNC model was believed to improve knowledge acquisition, behaviour change and peer support. Participants, staff and the majority of key informants expressed a high level of satisfaction with the PNC model. Sustainability and finding adequate human resources for PNCs remained challenging. Strategies to improve sustainability may include handing over some PNC tasks to members to increase their sense of ownership.

Innovative Three-Dimensional Microscopic Analysis of Uremic Growth Plate Discloses Alterations in the Process of Chondrocyte Hypertrophy: Effects of Growth Hormone Treatment.

Chronic kidney disease (CKD) alters the morphology and function of the growth plate (GP) of long bones by disturbing chondrocyte maturation. GP chondrocytes were analyzed in growth-retarded young rats with CKD induced by adenine intake (AD), control rats fed ad libitum (C) or pair-fed with the AD group (PF), and CKD rats treated with growth hormone (ADGH). In order to study the alterations in the process of GP maturation, we applied a procedure recently described by our group to obtain high-quality three-dimensional images of whole chondrocytes that can be used to analyze quantitative parameters like cytoplasm density, cell volume, and shape. The final chondrocyte volume was found to be decreased in AD rats, but GH treatment was able to normalize it. The pattern of variation in the cell cytoplasm density suggests that uremia could be causing a delay to the beginning of the chondrocyte hypertrophy process. Growth hormone treatment appears to be able to compensate for this disturbance by triggering an early chondrocyte enlargement that may be mediated by Nkcc1 action, an important membrane cotransporter in the GP chondrocyte enlargement.

Peer Mentorship via Mobile Phones for Newly Diagnosed HIV-Positive Youths in Clinic Care in Khayelitsha, South Africa: Mixed Methods Study.

BACKGROUND: Youths in South Africa are poor utilizers of HIV health services. Medecins Sans Frontieres has been piloting youth-adapted services at a youth clinic in Khayelitsha, including a peer virtual mentorship program over mobile phones, piloted from March 2015 to May 2016. OBJECTIVE: The objective of this study was to evaluate the effect of the peer mentorship program on youth engagement with HIV services and explore the acceptability of the program to both mentors and mentees. METHODS: Antiretroviral initiation, retention in care (RIC), and viral load suppression were compared between youths engaged in the virtual mentorship program and two matched controls. In-depth interviews were also conducted for 5 mentors and 5 mentees to explore acceptability and impact of the program. RESULTS: A total of 40 youths were recruited into the virtual mentorship program over the study period. Of these, data were obtained for 35 and 2 matched controls were randomly sampled for each. There was no difference in baseline demographics (eg, age, gender, and CD4 count). Mentees had increased antiretroviral initiation (28/35, 80% vs 30/70, 42% in matched controls) and viral load completion (28/35, 80% vs 32/70, 45%); however, no differences were found in viral load suppression or RIC at 6 or 12 months. Mentors reported being motivated to participate in the program because of previous personal struggles with HIV and a desire to help their peers. Mentees reported fears of disclosure and lack of acceptance of their status as barrier to accessing services, but they felt free to talk to their mentors, valued the mentorship program, and indicated a preference for phone calls. CONCLUSIONS: Peer mentorship in youths is acceptable to both mentors and mentees and appears to increase linkage to care and viral load completion rates.

A metagenomic study of patients with alveolar osteitis after tooth extraction. A preliminary case-control study.

OBJECTIVE: To identify the microbiome in sockets with alveolar osteitis and compare it with a control group using metagenomic techniques. MATERIALS AND METHODS: A case-control study was conducted in subjects that had undergone a tooth extraction. Microbiological samples were taken from the sockets of 10 patients with dry socket after tooth extraction (AO group) and 10 patients in whom exodontia resulted in no postoperative complications (control group). Bacterial DNA was isolated, and the 16S rRNA gene was amplified and sequenced. Multiplexed tag-encoded sequencing of DNA from the samples was performed, and the reads were processed by Metagenomic Rapid Annotation. RESULTS: A total of 151 different species were found: 55 bacteria were only found in the AO group, 51 were specific to the control group, and 45 were common to both groups. The most frequently found genera in both groups were Prevotella. Prevotella nanceiensis, Actinomyces odontolyticus, Treponema maltophilum, Veillonella dispar, Tannerella forsythia, and Leuconostoc mesenteroides were found in several patients with alveolar osteitis, with an abundance greater than 0.5%, and were absent in all the control group samples. CONCLUSIONS: Patients who develop alveolar osteitis after dental extractions might have a different microbiota from that of patients without postoperative complications. Since this is a preliminary report, further research is needed to assess whether bacteria play an important role in the etiology of dry socket. CLINICAL RELEVANCE: This study seems to indicate that bacteria may play an important role in the alveolar osteitis etiology. Thus, new prevention and treatment strategies should be considered.

Genomes of ubiquitous marine and hypersaline Hydrogenovibrio, Thiomicrorhabdus and Thiomicrospira spp. encode a diversity of mechanisms to sustain chemolithoautotrophy in heterogeneous environments.

Chemolithoautotrophic bacteria from the genera Hydrogenovibrio, Thiomicrorhabdus and Thiomicrospira are common, sometimes dominant, isolates from sulfidic habitats including hydrothermal vents, soda and salt lakes and marine sediments. Their genome sequences confirm their membership in a deeply branching clade of the Gammaproteobacteria. Several adaptations to heterogeneous habitats are apparent. Their genomes include large numbers of genes for sensing and responding to their environment (EAL- and GGDEF-domain proteins and methyl-accepting chemotaxis proteins) despite their small sizes (2.1-3.1 Mbp). An array of sulfur-oxidizing complexes are encoded, likely to facilitate these organisms' use of multiple forms of reduced sulfur as electron donors. Hydrogenase genes are present in some taxa, including group 1d and 2b hydrogenases in Hydrogenovibrio marinus and H. thermophilus MA2-6, acquired via horizontal gene transfer. In addition to high-affinity cbb3 cytochrome c oxidase, some also encode cytochrome bd-type quinol oxidase or ba3 -type cytochrome c oxidase, which could facilitate growth under different oxygen tensions, or maintain redox balance. Carboxysome operons are present in most, with genes downstream encoding transporters from four evolutionarily distinct families, which may act with the carboxysomes to form CO2 concentrating mechanisms. These adaptations to habitat variability likely contribute to the cosmopolitan distribution of these organisms.

Delamanid for rifampicin-resistant tuberculosis: a retrospective study from South Africa.

Experience with delamanid (Dlm) is limited, particularly among HIV-positive individuals. We describe early efficacy and safety data from a programmatic setting in South Africa.This was a retrospective cohort study of patients receiving Dlm-containing treatment regimens between November 2015 and August 2017. We report 12-month interim outcomes, sputum culture conversion (SCC) by months 2 and 6, serious adverse events (SAEs) and QT intervals corrected using the Frederica formula (QTcF).Overall, 103 patients were initiated on Dlm; 79 (77%) were HIV positive. The main indication for Dlm was intolerance to second-line anti-tuberculosis (TB) drugs (n=58, 56%). There were 12 months of follow-up for 46 patients; 28 (61%) had a favourable outcome (cure, treatment completion or culture negativity). Positive cultures were found for 57 patients at Dlm initiation; 16 out of 31 (52%) had SCC within 2 months and 25 out of 31 (81%) within 6 months. There were 67 SAEs reported in 29 patients (28%). There were four instances of QTcF prolongation >500 ms in two patients (2%), leading to permanent discontinuation in one case; however, no cardiac arrhythmias occurred.This large cohort of difficult-to-treat patients receiving Dlm for rifampicin-resistant TB treatment in a programmatic setting with high HIV prevalence had favourable early treatment response and tolerated treatment well. Dlm should remain available, particularly for those who cannot be treated with conventional regimens or with limited treatment options.

Antibiotic susceptibility of methicillin-resistant staphylococci (MRS) of food origin: A comparison of agar disc diffusion method and a commercially available miniaturized test.

Methicillin-resistant staphylococci (MRS) are a major concern to public and animal health. Thirty MRS (Staphylococcus aureus, S. cohnii, S. epidermidis, S. haemolyticus, S. hominis, S. lentus, S. lugdunensis, S. sciuri, and S. xylosus) isolates from meat and poultry preparations were tested for antimicrobial susceptibility to 11 antimicrobials (belonging to seven different categories) of clinical significance using both the standard agar disc diffusion method and a commercially available miniaturized system (Sensi Test Gram-positive). It is worth stressing that 16 isolates (53.33%) exhibited an extensively drug-resistant phenotype (XDR). The average number of resistances per strain was 4.67. These results suggest that retail meat and poultry preparations are a likely vehicle for the transmission of multi-drug resistant MRS. Resistance to erythromycin was the commonest finding (76.67% of strains), followed by tobramycin, ceftazidime (66.67%), ciprofloxacin (56.67%) and fosfomycin (53.33%). An agreement (kappa coefficient) of 0.64 was found between the two testing methods. Using the agar disc diffusion as the reference method, the sensitivity, specificity and accuracy of the miniaturized test were 98.44%, 69.44% and 83.33%, respectively. Most discrepancies between the two methods were due to isolates that were susceptible according to the disc diffusion method but resistant according to the miniaturized test (false positives).

Effect of sub-inhibitory concentrations of biocides on the architecture and viability of MRSA biofilms.

The effect of sub-minimum inhibitory concentrations (sub-MICs) of three biocides (benzalkonium chloride [BZK], trisodium phosphate [TSP] and sodium hypochlorite [SHY]) upon the architecture and viability of the biofilms formed by a methicillin-resistant Staphylococcus aureus strain of food origin (MRSA 48a) was investigated. Images were examined through confocal laser scanning microscopy (CLSM) after staining with SYTO9 and propidium iodide. Sub-MICs of BZK or TSP reduced the ability of MRSA to produce biofilm. In contrast, the presence of sub-MICs of SHY enhanced the biofilm-forming ability of MRSA when cells had undergone previous adaptation to this compound (biovolume in the observation field was 137,785.31 ± 47,682.79 µm3 for biofilms formed in the presence of SHY, and 70,204.13 ± 31,603.98 µm3 in the absence of biocides; P < 0.05). The largest amount of live (green stained) cells (P < 0.05) was observed in biofilms grown in the presence of SHY relative to the other conditions tested (58,999.75 ± 55,312.37 µm3vs 31,976.29 ± 38,594.98 µm3). Findings from the present work constitute the first report of biofilm production by MRSA being induced by sub-inhibitory concentrations of SHY. The data suggest that repeated use of SHY at low concentrations could represent a public health risk.

Effect of Sub-Lethal Concentrations of Biocides on the Structural Parameters and Viability of the Biofilms Formed by Salmonella Typhimurium.

This study aimed to investigate the effect of sub-minimum inhibitory concentrations (sub-MICs) of three food-grade biocides (benzalkonium chloride -BZK-, trisodium phosphate -TSP-, and sodium hypochlorite -SHY-) on Salmonella biofilms. The structural parameters and bacterial viability of the biofilms formed by a S. Typhimurium isolate from poultry was investigated by means of confocal laser scanning microscopy after staining with SYTO9 and propidium iodide. The MIC values for Salmonella cells before exposure to subinhibitory concentrations of biocides were 8.0 µg/mL (BZK), 18.0 mg/mL (TSP), and 6.0 mg/mL (SHY). The cultures exhibited a stable acquired tolerance to BZK and SHY. The maximum concentrations of biocides that allowed bacterial growth after several passages through gradually higher concentrations of such compounds were 30.4 µg/mL (BZK) and 10.1 mg/mL (SHY). The architecture and viability of S. Typhimurium biofilms varied in response to sub-MICs of different biocides. Previous adaptation to SHY enhanced (p < 0.001) biofilm formation (average biovolume in the observed field -14,161 µm2-: 139,856.15 ± 155,213.27 µm3) relative to unexposed cells (53,779.05 ± 55,535.62 µm3) and cells previously exposed to BZK (58,216.97 ± 58,644.45 µm3) or TSP (30,052.13 ± 28,290.56 µm3). This was particularly marked when biofilm was grown in the absence of biocides or in the presence of sub-MICs of SHY. The highest percentage of dead cells was shown by biofilms formed by cultures previously exposed to TSP relative to the other conditions tested (34.08% ± 13.74% vs. 23.70% ± 16.16%; p < 0.001). The importance of maintaining higher than MICs of SHY during sanitizing procedures to fight foodborne infections by Salmonella biofilms is highlighted.