Correction: Genovese et al. In Vitro Antibacterial, Anti-Adhesive and Anti-Biofilm Activities of Krameria lappacea (Dombey) Burdet & B.B. Simpson Root Extract against Methicillin-Resistant Staphylococcus aureus Strains. Antibiotics 2021, 10, 428.

The authors would like to make the following corrections to the published paper [...].

In Vitro Antibacterial, Anti-Adhesive and Anti-Biofilm Activities of Krameria lappacea (Dombey) Burdet & B.B. Simpson Root Extract against Methicillin-Resistant Staphylococcus aureus Strains.

Methicillin-resistant Staphylococcus aureus (MRSA) represents a serious threat to public health, due to its large variety of pathogenetic mechanisms. Accordingly, the present study aimed to investigate the anti-MRSA activities of Krameria lappacea, a medicinal plant native to South America. Through Ultra-High-Performance Liquid Chromatography coupled with High-Resolution Mass spectrometry, we analyzed the chemical composition of Krameria lappacea root extract (KLRE). The antibacterial activity of KLRE was determined by the broth microdilution method, also including the minimum biofilm inhibitory concentration and minimum biofilm eradication concentration. Besides, we evaluated the effect on adhesion and invasion of human lung carcinoma A549 cell line by MRSA strains. The obtained results revealed an interesting antimicrobial action of this extract, which efficiently inhibit the growth, biofilm formation, adhesion and invasion of MRSA strains. Furthermore, the chemical analysis revealed the presence in the extract of several flavonoid compounds and type-A and type-B proanthocyanidins, which are known for their anti-adhesive effects. Taken together, our findings showed an interesting antimicrobial activity of KLRE, giving an important contribution to the current knowledge on the biological activities of this plant.

Streptococcus agalactiae in pregnant women: serotype and antimicrobial susceptibility patterns over five years in Eastern Sicily (Italy).

Streptococcus agalactiae (also known Group B Streptococcus or GBS) represents the main pathogen responsible for early- and late-onset infections in newborns. The present study aimed to determine the antimicrobial susceptibility pattern and the capsular serotypes of GBS isolated in Eastern Sicily over 5 years, from January 2015 to December 2019. A total of 3494 GBS were isolated from vaginal swabs of pregnant women (37-39 weeks), as recommended by the Centers for Disease Control and Prevention. Capsular polysaccharide's typing of GBS was determined by a commercial latex agglutination test containing reagents to serotypes I-IX. The antimicrobial resistance pattern of GBS was determined through the disk diffusion method (Kirby-Bauer) and the double-disk diffusion test on Mueller-Hinton agar plates supplemented with 5% defibrinated sheep blood, according to the guidelines of the Clinical and Laboratory Standards Institute. Serotypes III (1218, 34.9%) and V (1069, 30.6%) were the prevalent colonizers, followed by not typable (570, 16.3%) and serotypes Ia (548, 15.7%), Ib (47, 1.3%), II (40, 1.1%), and IV (2, 0.1%). All 3494 clinical isolates were susceptible to cefditoren and vancomycin. Resistance to penicillin, ampicillin, levofloxacin, clindamycin, and erythromycin was observed in 6 (0.2%), 5 (0.1%), 161 (4.6%), 1090 (31.2%), and 1402 (40.1%) of the strains, respectively. Most of erythromycin-resistant GBS (1090/1402) showed the cMLSB phenotype, 276 the M phenotype, and 36 the iMLSB phenotype. Our findings revealed a higher prevalence of serotype III and a relevant resistance rate, among GBS strains, to the most frequently used antibiotics in antenatal screening.

Bioinspired benzoxanthene lignans as a new class of antimycotic agents: synthesis and Candida spp. growth inhibition.

In this work we synthetized the bioinspired benzoxanthene lignans (BXLs) 3, 14-22, and the phenazine derivative 23 as potential antimycotic agents. MICs and MFCs against Candida strains were determined. In a preliminary screening, compounds 3, 15, 20, 21, 22 were substantially inactive. Compounds 14 and 17 showed antifungal activity, being able to inhibit the growth of the majority of Candida strains with MIC values in the range 4.6-19.2 µM (14) and 26.0-104.3 µM (17); for three strains, the MICs were lower than those obtained using the antimycotic drug fluconazole. The three BXLs 18, 19 and 23 showed some MIC values lower than that of fluconazole; 18 was also active against two non-albicans Candida strains resistant to fluconazole. Phenazine 23, although active only against one strain (MIC = 1.3 µM), was one order of magnitude more potent than fluconazole. All the BXLs were fungicidal.

In vitro evaluation of biological activities of Orobanche crenata Forssk. leaves extract.

Orobanche crenata Forssk. (Orobanchaceae) is a holoparasitic plant noxious to legumes. Orobanchaceae are well known in traditional medicine for their hypotensive, antihyperglycemic, antispasmodic, analgesic and antimicrobial effects. In this work, the biological activities of the acetonic leaves extract were evaluated. Qualitative chemical analysis was determined through thin layer chromatography. Total phenols and flavonoids content was obtained by the Folin-Ciocalteu and the Aluminium chloride colorimetric methods, respectively. The antimicrobial activity was performed by the broth microdilution method. The extract showed antibacterial activity, particularly against Gram-positive strains, with MIC ranging from 376.00 to 3011.00 µg/ml. Besides, it exhibited antifungal effects on Candida spp. with MIC ranging from 94.10 to 3011.00 µg/ml. In addition, O. crenata inhibited superoxide anion formation and showed a DPPH quenching capacity, particularly at 80 µg/ml. Interestingly, our results are promising thus indicating the importance of O. crenata as a significant source of biologically active natural compounds.

Antimicrobial efficacy of cordless sonic or ultrasonic devices on Enterococcus faecalis-infected root canals.

AIM: The aim of the present study was to evaluate the immediate and residual antimicrobial activity of cordless sonic or ultrasonic devices on Enterococcus faecalis (E faecalis)-infected teeth. METHODS: A total of 140 single-rooted extracted teeth with E faecalis were grouped as follows (N = 15): conventional syringe irrigation with 3% sodium hypochlorite activated by ultrasonic device (group 1) or cordless ultrasonic device (group 2), EndoActivator (group 3) or without activation (group 4), conventional syringe irrigation with sterile bi-distilled water and ultrasonic device (group 5), EndoUltra (group 6), EndoActivator (group 7), or without activation (group 8). The remaining 20 teeth were used for positive and negative controls. Colony-forming units (CFU) and turbidity were recorded from bacteriological samples taken before and after irrigation and after 24 hours of re-incubation. Data were statistically analyzed using Student's t test, Mann-Whitney test, Kruskal-Wallis test, and Dunn's multiple comparison tests (P < .05). RESULTS: Groups 1 and 2 showed higher antimicrobial efficacy than groups 3 and 4 (P < .05). No bacteria reduction was found in groups 5-8 (P > .05). After 24 hours, regrowth of bacteria was not significantly different for all groups (P > .05). CONCLUSIONS: Ultrasound produced lower CFU and turbidity after treatment and after re-incubation of 24 hours than sonic or no activation.

Combined systemic (fluconazole) and topical (metronidazole + clotrimazole) therapy for a new approach to the treatment and prophylaxis of recurrent candidiasis.

Recurrent vulvovaginal candidiasis (RVVC) is an important pathological and infectious condition that can greatly impact a woman's health and quality of life. Clinical and epidemiological studies show that different types of therapies are able to eliminate the signs and symptoms of mycotic vaginitis in the acute phase, but so far none of these has proved able to significantly reduce the risk of long-term recurrence. In this review, based on the available literature and original data from a preliminary in-vitro microbiological study on the compatibility between fluconazole, clotrimazole and metronidazole a new therapeutic approach to RVVC is discussed and presented. The treatment proposed is a combined scheme using both systemic antimicrobial drug therapy with oral fluconazole 200 mg and topical drug therapy using the association metronidazole 500 mg and clotrimazole 100 mg (vaginal ovules) with adjuvant oral probiotic therapy. In detail, at the time of diagnosis in the acute symptom phase, we propose the following treatment scheme: fluconazole 200 mg on day 1, 4, 11, 26, then 1 dose/month for 3 months at the end of the menstrual cycle; plus metronidazole/clotrimazole ovules 1/day for 6 days the first week, then 1 ovule/day for 3 days the week before the menstrual cycle for 3 months; plus probiotic 1 dose/day for 10 days for 3 months starting from the second month to the end of the menstrual cycle. This scheme aims to address the recurrent infection aggressively from the outset by attempting not only to treat acute symptoms, but also to prevent a new event by countering many of the potential risk factors of recurrence, such as the intestinal Candida reservoir, the mycotic biorhythm, the formation of biofilm, the phenotype switching and the presence of infections complicated by the presence of C. non albicans or G. Vaginalis, without interfering, but rather favoring the restoration of the vaginal lactobacillus species. Future clinical studies will be useful to confirm the proposed scheme.

Antioxidant and antimicrobial properties of Casteanea sativa Miller chestnut honey produced on Mount Etna (Sicily).

The aim of this study was the evaluation of antibacterial and antioxidant properties of Monofloral Etna Castanea sativa Miller honeys. Escherichia coli ATCC 25,922, Pseudomonas aeruginosa ATCC 27,853, Enterococcus faecalis ATCC 29,211 and Staphylococcus aureus ATCC 29,213 were investigated for their susceptibilities to two different honeys. Antioxidant activity was evaluated by ORAC, NO scavenger assays, FRAP and DPPH. Antioxidant activity and antibacterial properties were compared with chestnut honeys from different geographical areas and with Manuka honey. UPLC-MS/MS was used for major components characteri sation.

Effects of a new combination of plant extracts plus d-mannose for the management of uncomplicated recurrent urinary tract infections.

Urinary tract infections (UTIs) are an economic burden for public health. The increasing prevalence of resistant bacteria which cause UTIs may be related to the inappropriate prescription of antibiotics. The aim of this preliminary study was to evaluate whether three different combinations of plant extracts plus d-mannose are effective in preventing the recurrence of UTIs. Three groups of patients received three combinations of plant extracts in conjunction with d-mannose. These were: berberine, arbutin and birch (group A); berberine, arbutin, birch and forskolin (group B); and proanthocyanidins (group C). The clinical recurrence of cystitis at the end of treatment and during follow-up was determined by comparison with baseline measurements using the microbiological assessment of urine samples, vaginal swabs and vaginal smear slides. Patients in groups A and B had a lower incidence of episodes of recurrent cystitis during treatment and follow-up, samples with a significantly lower median bacterial load and a reduction of the grade of lactobacillary flora compared to patients in group C.

Labeling quality and molecular characterization studies of products containing Lactobacillus spp. strains.

The objective of the study was to characterize at species level by phenotypic and different molecular methods the strains of Lactobacillus spp. used as constituents of five oral and four vaginal products. Susceptibilities to representative antibiotics were evaluated. In addition, total viable counts at mid and 3 months to deadline of shelf life, in the different formulations and the presence of eventual contaminant microorganisms were investigated.In all oral products the molecular characterization at species level of the strains of Lactobacillus spp. confirmed the strains stated on the label, except for one strain cited on the label as Lactobacillus casei, that our study characterized as Lactobacillus paracasei. In oral products total viable cell content complied with content claimed on the label. In three out four vaginal products (one product claimed "bacillo di Döderlein"), molecular characterization complied with the bacterial name stated on the label. Two vaginal products reported viable counts on the label that were confirmed by our study. The other vaginal products, which did not report bacterial counts on the label, showed a similar decrease of viable counts at different dates to deadline compared to the others. From all the tested products, contaminant microorganisms and acquired resistance to representative antibiotics by the probiotic strains were not detected.

Adhesive behaviour and virulence of coagulase negative staphylococci isolated from Italian cheeses.

Coagulase-negative staphylococci (CoNS) belong to saprophytic microbiota on the skin and mucous membranes of warm-blooded animals and humans, but are also isolated from foodstuffs such as meat, cheese, and milk. In other circumstances, some CoNS can act as pathogens. Thus the presence of CoNS may not be an immediate danger to public health, but can become a risk factor. In particular antibiotic-resistant genes could be transferred to other potentially pathogenic microorganisms. Furthermore, CoNS are known to be strong biofilm producers and this is also a risk factor for public health. The aim of the present work was to determine the genotypic and phenotypic profiles of 106 CoNS belonging to four different species isolated from five different Italian cheeses for the presence of some adhesion and virulence features. In order to verify a possible correlation between the formation of biofilm and staphylococcal virulence factors, we checked the presence of adhesin genes by PCR and we investigated the ability of these strains to make biofilm at different temperatures. Furthermore, in some conditions, we analyzed surface proteins and autolytic pattern of selected strains. In conclusion, we checked the presence of norA and mecA genes responsible for fluoroquinolones and methicillin resistance, respectively. We found resistant genes in a proportion of the food isolates in amounts of 9.4% (mecA) and 5.7% (norA). These data support the importance to continuously examine the microbiota not only for the creation of a database but also to safeguard public health.

Nanotechnology approaches for antibacterial drug delivery: Preparation and microbiological evaluation of fusogenic liposomes carrying fusidic acid.

Many antibacterial drugs have some difficulty passing through the bacterial cell membrane, especially if they have a high molecular weight or large spatial structure. Consequently, intrinsic resistance is shown by some bacterial strains. Reduced cell membrane permeability is one of the mechanisms of resistance known for fusidic acid (FUS), a bacteriostatic steroidal compound with activity limited to Gram-positive bacteria. Moreover, the lipophilic character of FUS has been shown to cause drug retention inside the bilayers of cell membranes, preventing its diffusion towards target sites inside the cytoplasm. Targeting antimicrobial agents by means of liposomes may be a valid strategy in the treatment of infections refractory to conventional routes of antimicrobial treatment. On this basis, loading of FUS in fusogenic liposomes (FLs) was planned in this study. Fusogenic small unilamellar vesicles loaded with FUS were produced to evaluate their influence on improving the cell penetration and antibacterial activity of the antibiotic. The produced carriers were technologically characterised and were subjected to an in vitro microbiological assay against several strains of Gram-negative and Gram-positive bacteria. The experimental results showed that encapsulating FUS in a liposomal carrier can improve antimicrobial efficacy and reduce the effective concentration required, probably through putative mechanisms of increased diffusion through the bacterial cell membrane. In fact, whilst free FUS was active only on the tested Gram-positive strains, incubation of FUS-loaded FLs exhibited growth inhibitory activity both against Gram-positive and Gram-negative strains. The lowest MICs were obtained against Staphylococcus epidermidis (≤0.15 µg/mL) and Acinetobacter baumannii (37.5 µg/mL) clinical strains.

Anti-Adhesion Activity of A2-type Proanthocyanidins (a Cranberry Major Component) on Uropathogenic E. coli and P. mirabilis Strains.

Urinary tract infections (UTIs) are relatively common in women and may be classified as uncomplicated or complicated, depending upon the urinary tract anatomy and physiology. Acute uncomplicated cystitis (AUC) occurs when urinary pathogens from the bowel or vagina colonize the periurethral mucosa and reach the bladder. The vast majority of episodes in healthy women involving the same bacterial strain that caused the initial infection are thought to be reinfections. About 90% of AUC are caused by uropathogenic Escherichia coli (UPEC), but Proteus mirabilis also plays an important role. Several studies support the importance of cranberry (Vaccinium macrocarpon) proanthocyanidins in preventing adhesion of P-fimbriated UPEC to uroepithelial cells. In this study, we evaluated the in vitro anti-adhesion activity of A2-linked proanthocyanidins from cranberry on a UPEC and Proteus mirabilis strains and their possible influence on urease activity of the latter. A significant reduction of UPEC adhesion (up to 75%) on the HT1376 cell line was observed vs. control. For the strains of P. mirabilis there was also a reduction of adhesion (up to 75%) compared to controls, as well as a reduction in motility and urease activity. These results suggest that A2-type cranberry proanthocyanidins could aid in maintaining urinary tract health.

Management of aerobic vaginitis.

Aerobic vaginitis is a new nonclassifiable pathology that is neither specific vaginitis nor bacterial vaginosis. The diversity of this microbiological peculiarity could also explain several therapeutic failures when patients were treated for infections identified as bacterial vaginosis. The diagnosis 'aerobic vaginitis' is essentially based on microscopic examinations using a phase-contrast microscope (at ×400 magnification). The therapeutic choice for 'aerobic vaginitis' should take into consideration an antibiotic characterized by an intrinsic activity against the majority of bacteria of fecal origin, bactericidal effect and poor/absent interference with the vaginal microbiota. Regarding the therapy for aerobic vaginitis when antimicrobial agents are prescribed, not only the antimicrobial spectrum but also the presumed ecological disturbance on the anaerobic and aerobic vaginal and rectal microbiota should be taken into a consideration. Because of their very low impact on the vaginal microbiota, kanamycin or quinolones are to be considered a good choice for therapy.

Occurrence of extended spectrum beta-lactamases among isolates of Enterobacteriaceae from urinary tract infections in southern Italy.

The present investigation was undertaken to assess the prevalence of extended-spectrum beta-lactamases (ESbetaLs) among urinary tract infection (UTI) isolates. During 4 months in 2004, a total of 650 Enterobacteriaceae strains from UTIs was collected by five clinical microbiology laboratories located in southern Italy and the beta-lactamase production was investigated. A total of 50 of the 650 isolates were double-disk positive and suspected of producing an ESbetaL; Escherichia coli (36.0%) and Klebsiella pneumoniae (32.0%) were the most common species among all ESbetaL producers. Characterization of ESbetaL determinants was carried out by the colony blot hybridization method, and polymerase chain reaction (PCR) and DNA sequencing in order to identify the presence of bla (TEM), bla (SHV), bla (PER), and bla (CTX-M) determinants. The ESbetaL variants found in this study were the following: TEM-15, TEM-24, TEM-52, TEM-134, SHV-12, CTX-M-1, CTX-M-3, CTX-M-15, and PER-1. As expected, the majority of the isolates were found to be susceptible to imipenem (94%), cefepime (54%) and piperacillin-tazobactam (54%). The results of this survey show the prevalence of ESbetaL enzymes among enterobacterial pathogens causing UTIs in southern Italy.

Fosfomycin tromethamine in uncomplicated urinary tract infections: a clinical study.

The aim of our study was to verify if the empiric therapy with a single dose of 3 g fosfomycin tromethamine in patients with uncomplicated urinary tract infections (UTIs) was able to clinically resolveand to microbiologically eradicate the infection. A total of 387 out of the 400 patients (274 cases with acute and 113 cases with recurrent uncomplicated UTIs) were enrolled in the clinical study. Clinical and microbiological assessments were performed before and at 8-10 days after the administration. At follow-up high clinical recovery (88.9%) and bacteriological (94.9%) eradication rates were achieved. Gastrointestinal side effects were found in only 4.3% of patients. In conclusion, a single-dose administration regimen of fosfomycin tromethamine should be encouraged as a first choice of drug therapy for uncomplicated UTIs.

Exploring the variability in antibiotic prescribing profiles among paediatricians from two different areas of Italy.

We carried out a multicentre community-based study in order to describe the antibiotic therapeutic approach of paediatricians from two different areas of Italy in the treatment of respiratory tract infection (RTIs), and to assess which factors are involved in a possible variability of prescribing habits. Forty paediatricians participated in the study between October 1998 and April 1999. They had to complete a questionnaire for each therapeutic intervention resulting in an antibiotic prescription. A logistic regression model was used to identify possible predictors in choosing parenteral antibiotics for the treatment of RTIs. In 2 975 questionnaires of antibiotic treatment, RTIs represented 90.2% of the total antibiotics used. Upper respiratory tract infections were the most commonly treated diagnostic group (59.6%), followed by lower respiratory tract infections (20.4%), and middle ear infections (19.8%). Statistically significant differences between northern and southern Italy were reported in the antibiotic prescription profile and the duration of the therapy. Another marked difference was reported in the frequency of laboratory analysis requests. The logistic regression model indicated that the use of parenteral antibiotics appears significantly related to the type of infections [lower RTIs: (OR: 3.99; 95% CI: 2.49-6.37)], the geographic location [northern Italy: (OR: 0.20; 95% CI: 0.20-0.39)], and the presence of concurrent diseases (OR: 3.21; 95% CI: 1.46-7.02). The lack of adherence to clinical guidelines and the marked variability of antibiotic prescription rates between different areas of the country appear to be related to factors other than bacterial resistance, and highlight the importance of carrying out educational programmes targeted at the national level for improving the antibiotic prescription habits for the treatment of RTIs.

Erythromycin resistance in italian isolates of Streptococcus pyogenes and correlations with pulsed-field gel electrophoresis analysis.

Erythromycin resistance among Streptococcus pyogenes strains has been reported in Italy at high rates during the last few years. A total of 152 erythromycin-resistant isolates of this species from southern Italian regions were characterized for the macrolide-resistance phenotype and screened by PCR for the corresponding genetic determinant. A close correlation was found between these phenotypic/genotypic data concerning macrolide resistance and results of Sma I macrorestriction fragment patterns (PFGE) analysis. In fact, the vast majority of the isolates assigned to individual PFGE classes mostly belonged to a single phenotype of macrolide resistance. All untypeable isolates belonged to the M phenotype. Twenty-two distinct PFGE types were recognized, of which 11 were recorded in only one isolate (one-strain type); about 50% of typeable isolates fell into five type clusters and 70% in seven. The increased erythromycin resistance among Italian isolates of S. pyogenes does not appear to be due to the spread of a single clone, but results indicate that the majority of group A streptococci examined are probably spread from a limited number of clones.