Detection of KPC-216, a Novel KPC-3 Variant, in a Clinical Isolate of Klebsiella pneumoniae ST101 Co-Resistant to Ceftazidime-Avibactam and Cefiderocol.

BACKGROUND: Carbapenemase-producing Klebsiella pneumoniae (CP-KP) represents a global threat to public health, with limited antimicrobial therapeutic options. In this study, we analyzed a ceftazidime/avibactam (CAZ-AVI)-resistant K. pneumoniae isolate obtained from a patient previously exposed to CAZ-AVI expressing a novel K. pneumoniae carbapenemase (KPC)-3 variant. METHODS: Antimicrobial susceptibility testing was performed using reference broth microdilution. Whole-genome sequencing (WGS) was performed using Illumina and Nanopore Technologies. Short- and long-reads were combined with Unicycler. Assemblies were investigated for multilocus sequence typing (MLST), antimicrobial resistance genes, porins, and plasmids. RESULTS: The K. pneumoniae isolate (KP_RM_1) was resistant to CAZ-AVI, expanded-spectrum cephalosporins, amikacin, ertapenem, and cefiderocol (FDC) but was susceptible to tigecycline, colistin, trimethoprim/sulfamethoxazole, meropenem-vaborbactam, and imipenem-relebactam. WGS revealed that the KP_RM_1 genome is composed of a single chromosome of 5 Mbp and five circular plasmids. Further analysis showed the presence of novel blaKPC-216 located on a 72 kb plasmid. KPC-216 differs from KPC-3 by a Lysin (K) insertion at position 168 (+K168). CONCLUSIONS: We report the identification of a new KPC-3 variant associated with CAZ-AVI resistance. The KPC variants associated with CAZ-AVI resistance should be determined to promptly inform clinicians and start the appropriate antimicrobial therapy.

Streptococcus pneumoniae primary peritonitis mimicking acute appendicitis in an immunocompetent patient: a case report and review of the literature.

INTRODUCTION: Primary peritonitis without an identifiable intra-abdominal source is extremely rare in healthy individuals; it is commonly seen in cases of nephrotic syndrome, cirrhosis and end-stage liver disease, ascites, immunosuppression, and inflamed peritoneum due to pre-existing autoimmune and oncological conditions. CASE PRESENTATION: We present the case of a 68-year-old Caucasian woman operated on due to acute abdomen with a provisional diagnosis of acute appendicitis. During the operation a small amount of free intra-abdominal fluid was found. Her uterus, ovaries, and fallopian tubes were macroscopically normal. Therefore, with the suspicion of appendicitis, appendectomy was performed. Her blood cultures were negative while peritoneal fluid was positive for capsulated form of Streptococcus pneumoniae. A 30-day follow-up was performed and she was asymptomatic without any sign of infection. DISCUSSION: Streptococcus pneumoniae commonly causes upper respiratory tract infection and cutaneous infections. It very rarely causes gastrointestinal infection and it is very rarely responsible for primary peritonitis and septic shock syndrome. CONCLUSION: Pneumococcal peritonitis has a rare occurrence and represents a clinical challenge because of its subtle and non-specific clinical findings. The interest in our case lays in the relatively rare diagnosis of primary peritonitis mimicking acute appendicitis.

In Vitro Activity of Tea Tree Oil Vaginal Suppositories against Candida spp. and Probiotic Vaginal Microbiota.

The aim of this work is to evaluate the in vitro microbicidal activity of vaginal suppositories (VS) containing tea tree oil (TTO-VS) towards Candida spp. and vaginal probiotics. A total of 20 Candida spp. strains, taken from patients with vaginitis and from an established type collection, including reference strains, were analysed by using the CLSI microdilution method. To study the action of VS towards the beneficial vaginal microbiota, the sensitivity of Bifidobacterium animalis subsp. lactis (DSM 10140) and Lactobacillus spp. (Lactobacillus casei R-215 and Lactobacillus acidophilus R-52) was tested. Both TTO-VS and TTO showed fungicidal activity against all strains of Candida spp. whereas placebo-VS or the Aloe gel used as controls were ineffective. The study of fractional fungicidal concentrations (FFC) showed synergistic interaction with the association between Amphotericin B and TTO (0.25 to 0.08 µg/ml, respectively) against Candida albicans. Instead, the probiotics were only affected by TTO concentration ≥ 4% v/v, while, at concentrations < 2% v/v, they remained viable. TTO-VS exhibits, in vitro, a selective fungicidal action, slightly affecting only the Bifidobacteriun animalis strain growth belonging to the vaginal microbiota. In vivo studies are needed to confirm the efficacy to prevent acute or recurrent vaginal candidiasis.

Worrisome trend of new multiple mechanisms of linezolid resistance in staphylococcal clones diffused in Italy.

In order to assess the frequency of clinically relevant linezolid-resistant staphylococcal isolates, and the role of linezolid in maintaining and coselecting multiple resistance mechanisms (cfr, 23S rRNA, L3/L4 mutations), a prospective Italian study was performed from 2010 to 2011 to confirm the diffusion of three major multidrug-resistant clones (ST2, ST5, ST23).

Post-sternotomy chronic osteomyelitis: is sternal resection always necessary?

OBJECTIVES: The goal of this study was to investigate alternative strategies to the sternal resection in the treatment of post-sternotomy osteomyelitis. We report our experience in the treatment of chronic infection of median sternotomy following open heart surgery without sternal resection. METHODS: A 4-year retrospective study was performed, consisting of 70 patients affected by post-sternotomy sternocutaneous fistulas due to chronic osteomyelitis: 45 patients underwent only medical treatment and 25 underwent steel wire removal and surgical debridement (conservative surgery). Of the 25, 7 patients underwent an additional vacuum assisted closure (VAC) therapy due to widespread infected subcutaneous tissue. The diagnosis of osteomyelitis was supported via 3D CT scan images. RESULTS: Complete wound healing was achieved in 67 patients including a patient who achieved healing after being affected by a fistula for over 24 years before coming under our observation, another, affected by mycobacteria other than tuberculosis osteomyelitis, who needed antimicrobial treatment for a period of 30 months and 2 who were affected by Aspergillus infection and needed radical cartilage removal. Fistula relapses were observed in 6 patients of the total 70, possibly due to the too short-term antibiotic therapy used in the presence of coagulase-negative Staphylococcus (CoNS) with multiple resistances and in the presence of Corynebacterium species. CONCLUSIONS: Post-sternotomy chronic osteomyelitis can be successfully treated mainly by systemic antimicrobial therapy alone, without mandatory surgical treatments, provided that accurate microbiological and radiological studies are performed. The presence of CoNS and Corynebacterium species seemed to be associated with a need for a prolonged combined antimicrobial therapy with a minimum of 6 months up to a maximum of 18 months. The CT scan and the 3D reconstruction of the sternum proved to be a good method to evaluate the status of the sternum and support the treatments. The VAC therapy was not useful in treating osteomyelitis, although, if used appropriately in the postoperative deep sternal wound infection with the sponge fitted between the sternal edges, it seems to be an effective method to eradicate the infection in the sternum and to prevent chronic osteomyelitis.

Improved results of the vacuum assisted closure and Nitinol clips sternal closure after postoperative deep sternal wound infection.

OBJECTIVE: Postoperative deep sternal wound infection is a severe complication of cardiac surgery, with a high mortality rate and a high morbidity rate. The objective of this prospective study is to report our experience with the vacuum assisted closure (VAC) system for the management of deep wound infection. We also devised an innovative closure technique post VAC therapy using thermo reactive clips. The advantage of this technique is that the posterior face of the sternum does not have to be separated from the mediastinal structures thus minimising the risk of damage. METHODS: From October 2006 to October 2008, we prospectively evaluated 21 patients affected by mediastinitis after sternotomy. Nineteen patients had sternotomy for coronary artery bypass grafting (CABG), one patient for aortic valve replacement (AVR) and another one for ascending aortic replacement (AAR). All patients were treated with the VAC system at the time of infection diagnosis. When the wound tissue appeared viable and the microbiological cultures were negative, the chest was closed using the most suitable procedure for the patient in question; nine patients were closed using pectoralis flaps, nine patients using Nitinol clips, one patient with a combined technique (use of Nitinol clips and muscle flap), one patient with a direct wound closure and another patient, who needed AAR with a homograft performed in another institution, was closed using sternal wires. RESULTS: We had no mortality; wound healing was successfully achieved in all patients. In more than 50% of the patients, the VAC therapy allowed direct sternal resynthesis. The average duration of the vacuum therapy was 26 days (range 14-37 days). CONCLUSIONS: VAC is a safe and effective option in the treatment of post-sternotomy mediastinitis, with excellent survival and immediate improvement of local wound conditions; furthermore, the use of Nitinol clips after VAC therapy demonstrated to be a safe and non-invasive option for sternal resynthesis. After VAC therapy, a reduction in number of muscular flaps used and an increase of direct sternal resynthesis were observed.

Diagnostic difficulties of Lactobacillus casei bacteraemia in immunocompetent patients: a case report.

INTRODUCTION: Lactobacilli are currently proposed as probiotic agents in several dietary products. In blood cultures, they are usually considered as contaminants, but in recent years they have been recognized as causal infectious agents of endocarditis, urinary tract infections, meningitis, intra-abdominal infections and bacteraemia. CASE PRESENTATION: We report a case of Lactobacillus casei bacteraemia in a 66-year-old immunocompetent man with a history of fever of unknown origin. Leuconostoc bacteraemia was demonstrated by blood culture, but a later polymerase chain reaction analysis with sequencing of 16S ribosomal RNA identified Lactobacillus casei and a successful antibiotic therapy was performed. CONCLUSION: Bacteraemia caused by probiotic organisms is rare but underestimated, since they are normally regarded as contaminants and their role as primary invaders is not always easily established. Although the consumption of probiotic products cannot be considered a risk factor in the development of diseases caused by usually non-pathogenic bacteria, specific individual clinical histories should be taken into account. This report should alert both clinicians and microbiologists to the possibility of unusual pathogens causing serious illnesses and to the use of 16S ribosomal RNA sequencing for molecular identification as a powerful tool in confirming the diagnosis of infrequent pathogens.

Decrease of methicillin resistant Staphylococcus aureus prevalence after introduction of a surgical antibiotic prophylaxis protocol in an Italian hospital.

The use of antimicrobials is an important factor contributing to the emergence of antibiotic resistance. The goal of our study was to evaluate the impact of the introduction of an antibiotic surgical prophylaxis protocol on the prevalence of methicillin resistant Staphylococcus aureus (MRSA) infections in a tertiary care hospital. The protocol of surgical antibiotic prophylaxis was designed by a multidisciplinary team and was implemented in December 2001. Between January 2002 and December 2002, pharmacy, laboratory and active surveillance-records were prospectively reviewed to calculate prevalence rates of defined daily doses (DDD), microorganism isolation and health-care related infections. A progressive decrease from 1.58 to 0.56 of MRSA isolations per 1000 patient-days and from 76.4% to 29.4% MRSA prevalence rate was reported (p<0.001). Monthly prevalence rates of MRSA showed a significant linear correlation with the reduction of the DDD of the 3rd generation cephalosporins (r=0.90; p<0.001). MRSA surgical site and blood stream infections decreased from 78% to 38% and from 89% to 38%, respectively (p=0.017 and p=0.026). In our experience, the reduction of 3rd generation cephalosporin use was an effective strategy to reduce the MRSA infection rate and was associated with the reduction of the overall expenditure for antibiotics in the hospital.