Silvana Noviello

Epidemiology and microbiology of skin and soft tissue infections.

Purpose of review Skin and soft tissue infections (SSTIs) are a broad spectrum of diseases, including uncomplicated and complicated infections. Herein, we review the current epidemiology and microbiology of SSTIs. Recent findings In the last decades, a significant growing trend of SSTIs both in the community and healthcare settings with a dramatic increase of the economic burden for these diagnoses was observed. Several observational studies found that SSTIs are a substantial cause of ambulatory and emergency department visits, and of hospitalizations. Although, microbiology of SSTIs changes according to the clinical feature and the severity of illness, Staphylococcus aureus being the leading cause of both uncomplicated infections and complicated infections. Moreover, the increasing prevalence of infections because of multidrug-resistant bacteria, mainly methicillin-resistant S. aureus (both community-acquired and healthcare-associated methicillin-resistant S. aureus), are associated with significantly increased morbidity, mortality, length of hospital stay, and costs, compared with infections because of susceptible strains. Moreover, although it is unclear whether high vancomycin minimum inhibitory concentration is associated with a worse outcome, it poses a further challenge for the clinicians. Summary The understanding of the current epidemiology and microbiology of SSTIs is indicated for an appropriate antimicrobial therapy and an overall optimal management of SSTIs.

Macrolide-resistance genes in clinical isolates of Streptococcus pyogenes.

Macrolide-resistance genes were investigated in 103 macrolide-resistant strains of Streptococcus pyogenes, isolated from children with pharyngotonsillitis. The presence of mef(A), erm(B), and erm(TR) genes was detected by PCR. mef(A) was found in 48 out of 103 (46.6%) strains, whereas erm(B) was detected in 43 isolates (41.7%). All mef(A) strains showed a typical M phenotype (resistance to 14- and 15-membered macrolides, and sensitivity to lincosamides and streptogramin B), whereas erm(B) strains had the MLSB phenotype (resistance to macrolides, lincosamides, and streptogramin B antibiotics). erm(TR) was found in 10 strains, always together with other resistance genes. In seven cases erm(TR) was associated with erm(B), and three cases with mef(A). In two isolates with the M phenotype (1.9%), it was not possible to detect the presence of any of the three macrolide resistance genes tested. Inducible resistance to macrolides was shown for 24 out of the 53 MLSB strains. Analysis of macrorestriction fragment patterns by pulsed-field gel electrophoresis showed that erythromycin-resistant S. pyogenes are polyclonal, however each phenotype, MLSB and M, formed essentially homogeneous groups.

Comparative in vitro activity of older and newer fluoroquinolones against respiratory tract pathogens.

The aim of this study was to evaluate the antibacterial activity of older (ciprofloxacin and ofloxacin) and newer (moxifloxacin, grepafloxacin, sparfloxacin and levofloxacin) fluoroquinolones. Minimal inhibitory concentrations (MICs) were determined, according to the NCCLS guidelines, against the following respiratory tract pathogens: penicillin-susceptible and -resistant Streptococcus pneumoniae, β-lactamase-positive and βlactamase-negative Haemophilus influenzae and β-lactamase-positive Moraxella catarrhalis. In addition, we evaluated the minimal bactericidal concentrations of the same antibiotics against all the pneumococci and the haemophili. Finally, the activity of ciprofloxacin, ofloxacin, sparfloxacin and moxifloxacin against 15 pneumococci were investigated by time-kill analysis. All fluoroquinolones tested exhibited a similar, good activity against H. influenzae and M. catarrhalis. Against S. pneumoniae, irrespective of penicillin susceptibility, moxifloxacin, grepafloxacin, sparfloxacin and levofloxacin exhibited excellent activity, better than ciprofloxacin and ofloxacin. Time-kill analysis showed that 99.9% killing of all strains was obtained after 24 h with moxifloxacin at 2 × MIC, whereas other antimicrobials obtained similar results at 4 × MIC. Moxifloxacin is characterized by an improved activity against respiratory pathogens, including penicillin-resistant and -susceptible S. pneumoniae. Its activity is not influenced by β-lactamase production. These results suggest that moxifloxacin represents a promising alternative for treatment of respiratory tract infections.

Cefodizime in skin suction blister fluid and serum following a single intravenous or intramuscular dose in adult patients.

Abstract Cefodizime is a third generation cephalosporin for parenteral use. The phar-macokinetics of this cephem antibiotic were determined in serum and skin suction blister fluid (SBF) after intravenous (i.v.) or intramuscular (i.m.) administration of a single 1 g dose in 8 adult patients with normal renal and hepatic function who volunteered for the study. The concentration versus time curve showed a slower elimination rate from the extravascular compartment: the half-lives were 4.4±0.5 and 5.4±0.4 hours after i.v. and i.m. route respectively. The relatively long elimination half-life in SBF with a mean residence time of about 8 hours allows the use of cefodizime once-a-day for the treatment of infections due to sensitive pathogens.

Deep tissue biopsy vs. superficial swab culture, including microbial loading determination, in the microbiological assessment of Skin and Soft Tissue Infections (SSTIs)

Thirty-two patients affected by SSTIs including DFIs were enrolled between 2013 and 2014. Superficial swab was obtained before and after cleansing with sterile saline, and after ultrasonic debridement; deep tissue biopsy was obtained from ulcer base. Samples were diluted with 1 mL of saline, serial 10-fold dilutions to 10−6 were made and 50 μL of each dilution was plated onto appropriate media. Bacteria were identified by Vitek II system. Microbial load was expressed as CFU/mL. Statistical analysis was performed by χ2. Incidence of Gram positives was higher than Gram negatives (S. aureus and P. aeruginosa being the most frequent); concordance (same bacteria isolated before and after debridement) never exceeded 60%. Ultrasonic debridement significantly reduced bacterial load or even suppressed bacterial growth. While reliability of superficial swab is poor for microbiological diagnosis of SSTIs, swabbing after ultrasonic debridement and biopsy of the ulcer base may be equally reliable.

Management of upper respiratory tract infections in primary care in Italy: a national survey

This prospective study, carried out in Italy during the winter of 1998 by the means of questionnaires, was designed to investigate the diagnostic and therapeutic approach of the Italian general practitioners (GPs) to the management of acute upper respiratory tract infections (URTIs) in adult outpatients. A total of 354 GPs were questioned about ten adult patients each who had visited the surgery with an URTI requiring an antibiotic prescription. Our data showed there was a tendency to prescribe antibiotics only on the basis of clinical diagnosis, microbiological investigations being required very rarely. Orally administered antibiotics were preferred and compliance with the number of daily doses strongly influenced the antibiotic prescription. In patients affected by more severe infections, injectable antibiotics were frequently prescribed.

Diagnostic and therapeutic appropriateness in bone and joint infections: results of a national survey

The impact of infectious diseases (ID) specialist consultation in the management of many types of bacterial infections has been fully demonstrated but not for bone and joint infections (BJIs). Nineteen ID Italian centres collected of data from June 2009 to May 2012. Italian guidelines (2009) were used to determine the appropriateness of the diagnostic and therapeutic process of BJIs before and after consulting an ID specialist. Data on 311 patients were collected: 111 cases of prosthetic joint infection, 99 osteomyelitis, 64 spondylodiscitis and 37 fixation device infection. A significant increase of microbiological investigations, imaging techniques and blood inflammation markers were noted after consulting the ID specialist. Moreover, inappropriateness of treatment duration, dosage, and number of administrations significantly decreased after consultation. Infectious disease specialist intervention in the management of BJIs significantly increases the appropriateness both in performing instrumental and laboratory analysis, but especially in determining the correct therapy.

Epidemiology and antibiotic resistance in a large Italian teaching hospital

Abstract We focused our attention on susceptibility profile of Acinetobacter spp., Pseudomonas spp., and Klebsiella spp. isolated from biological specimens at the University Hospital of Salerno between June 2011 and October 2012. Acinetobacter, with a prevalence of Acinetobacter baumannii (97%) presented a high range of resistance to the antimicrobials considered, excluding colistin (COL). Klebsiella spp. isolates, with a prevalence of Klebsiella pneumoniae (90%), presented a variable pattern of resistance [from 9·8% for COL to 50% for levofloxacin (LEV)]. Extended-spectrum beta-lactamases production was detected in 15% of isolates. Most Pseudomonas isolates were P. aeruginosa with a high rate of resistance (95% to amoxicillin/clavulanate and trimethoprim/sulfamethoxazole, and <50% to the other antibiotics). Colistin remained the most effective drug tested. This study provided useful information of the local bacterial epidemiology hopefully permitting to establish a more effective empirical therapy, preventing the inappropriate use of antibacterial agents and possibly limiting the diffusion of antibacterial resistance.

Intestinal helminths in immigrants in Naples (Italy): a comparison between two different diagnostic techniques

Objective To compare two different Methods for detection of intestinal parasitic in immigrants from high risk geographic areas for intestinal parasitic diseases.

Comment on: Outpatient parenteral antibiotic therapy (OPAT) for bone and joint infections: experience from a UK teaching hospital-based service

Depending on local, environmental factors, such as lymphatic drainage, other organs can show symptomatic disease. It is probably more than coincidence that WD and lepromatous leprosy both show lymphangiectasia. T. whipplei and Mycobacteria leprae have much in common: they belong to the Actinobacteria class; ostensibly show tropism for macrophages; neither disease is associated with increased susceptibility to other pathogens; and the level of activation of macrophages (the DTH response) predicts the disease course and clinical manifestations, ranging from focal inflammatory disorders with few detectable organisms (high activation) to widespread, multiorgan infiltrates with abundant organisms (no activation). While an intrinsic defect in macrophage or lymphocyte function cannot be excluded as the underlying cause of WD, the consequences of systemic antigenaemia and lymphatic failure readily explain the absence of specific immunity and life-long susceptibility to T. whipplei.