An outbreak of wound infection in cardiac surgery patients caused by Enterobacter cloacae arising from cardioplegia ice

Two Newly Isolated Enterobacter-Specific Bacteriophages: Biological Properties and Stability Studies

In an era of antibiotic therapy crisis caused by spreading antimicrobial resistance, and when recurrent urinary tract infections constitute a serious social and medical problem, the isolation and complex characterization of phages with a potential therapeutic application represents a promising solution. It is an inevitable, and even a necessary direction in the development of current phage research. In this paper, we present two newly isolated myoviruses that show lytic activity against multidrug-resistant clinical isolates of Enterobacter spp. (E. cloacae, E. hormaechei, and E. kobei), the genomes of which belong to a poorly represented phage group. Both phages were classified as part of the Tevenvirinae subfamily (Entb_43 was recognized as Karamvirus and Entb_45 as Kanagawavirus). Phage lytic spectra ranging from 40 to 60% were obtained. The most effective phage-to-bacteria ratios (MOI = 0.01 and MOI = 0.001) for both the phage amplification and their lytic activity against planktonic bacteria were also estimated. Complete adsorption to host cells were obtained after about 20 min for Entb_43 and 10 min for Entb_45. The phage lysates retained their initial titers even during six months of storage at both −70 °C and 4 °C, whereas storage at 37 °C caused a complete loss in their activity. We showed that phages retained their activity after incubation with solutions of silver and copper nanoparticles, which may indicate possible synergistic antibacterial activity. Moreover, a significant reduction in phage titers was observed after incubation with a disinfectant containing octenidinum dihydrochloridum and phenoxyethanol, as well as with 70% ethanol. The observed maintenance of phage activity during incubation in a urine sample, along with other described properties, may suggest a therapeutic potential of phages at the infection site after intravesical administration.

Food Hygiene Surveillance in Italy: Is Food Ice a Public Health Risk?

Food ice is used as an ingredient or as a coolant in drinks and in the storage of food, especially fishery products. Studies show that ice can be polluted both by chemical substances and by bacteria and fungi. In particular, the presence of fungi in these food matrices has acquired an important role in Public Health, as it can represent a risk factor for fungal complications in immunocompromised subjects. In the present study we evaluated the hygiene–sanitary quality of food ice from public and collective catering establishments in a large area of Southern Italy, investigating the mandatory parameters (Escherichia coli, coliform and Enterococci) and some accessory parameters (Staphylococcus aureus, Pseudomonas aeruginosa and fungi) provided for Italian Legislative Decree 31/01. Although 54.5% of samples were compliant, the results highlight a vast contamination of food ice by bacteria and fungi. In particular, 95.8% of samples were contaminated by fungi, stressing no difference between compliant and non-compliant samples. Their presence is generally attributable to the poor sanitation conditions in the production and/or administration phase and to the incorrect sanitization and ordinary maintenance procedures. It seems appropriate to suggest the need to carry out a specific risk assessment with respect to the self-control plans.

A recurrent and transesophageal echocardiography-associated outbreak of extended-spectrum β-lactamase-producing Enterobacter cloacae complex in cardiac surgery patients

Background

We report a recurrent outbreak of postoperative infections with extended-spectrum β-lactamase (ESBL)–producing E. cloacae complex in cardiac surgery patients, describe the outbreak investigation and highlight the infection control measures.

Methods

Cases were defined as cardiac surgery patients in Ghent University Hospital who were not known preoperatively to carry ESBL-producing E. cloacae complex and who postoperatively had a positive culture for this multiresistant organism between May 2017 and January 2018. An epidemiological investigation, including a case-control study, and environmental investigation were conducted to identify the source of the outbreak. Clonal relatedness of ESBL-producing E. cloacae complex isolates collected from case patients was assessed using whole-genome sequencing–based studies.

Results

Three separate outbreak episodes occurred over the course of 9 months. A total of 8, 4 and 6 patients met the case definition, respectively. All but one patients developed a clinical infection with ESBL-producing E. cloacae complex, most typically postoperative pneumonia. Overall mortality was 22% (4/18). Environmental cultures were negative, but epidemiological investigation pointed to transesophageal echocardiography (TEE) as the outbreak source. Of note, four TEE probes showed a similar pattern of damage, which very likely impeded adequate disinfection. The first and second outbreak episode were caused by the same clone, whereas a different strain was responsible for the third episode.

Conclusions

Health professionals caring for cardiac surgery patients and infection control specialists should be aware of TEE as possible infection source. Caution must be exercised to prevent and detect damage of TEE probes.

Enterobacter Strains Might Promote Colon Cancer

Many studies have been performed to determine the interaction between bacterial species and cancer. However, there has been no attempts to demonstrate a possible relationship between Enterobacter spp. and colon cancer so far. Therefore, in the present study, it is aimed to investigate the effects of Enterobacter strains on colon cancer. Bacterial proteins were isolated from 11 Enterobacter spp., one Morganella morganii, and one Escherichia coli strains, and applied onto NCM460 (Incell) and CRL1790 (ATCC) cell lines. Cell viability and proliferation were determined in MTS assay. Flow Cytometry was used to detect CD24 level and apoptosis. Real-Time PCR studies were performed to determine NFKB and Bcl2 expression. Graphpad Software was used for statistical analysis. The results showed that proteins, isolated from the Enterobacter spp., have significantly increased cell viability and proliferation, while decreasing the apoptosis of the cell lines tested. The data in the present study indicated that Enterobacter strains might promote colon cancer. Moreover, Enterobacter spp. could be a clinically important factor for colon cancer initiation and progression. Studies can be extended on animal models in order to develop new strategies for treatment.

Involvement of Enterobacter cloacae in the mortality of the fish, Mugil cephalus

AIMS

To identify the causative agent of the mortality in the fish, Mugil cephalus, in Muttukadu lagoon.

METHODS AND RESULTS

An enteric bacterium from the kidneys of moribund fish M. cephalus, was isolated and identified as Enterobacter cloacae (MK). Mugil cephalus was experimentally infected by this isolate and was re-isolated from the kidneys of the moribund fish. Enterobacter cloacae isolates from the lagoon water (MW1, MW2 and reference strain ATCC 13047) and the reference strain were not able to induce similar pathogenesis. The putative factor imparting pathogenicity to the MK isolate was identified as a cationic molecule, which migrated towards the cathode on agarose gel electrophoresis.

CONCLUSIONS

The Ent. cloacae (MK) isolate harbouring a cationic factor was the causative agent for the mortality of M. cephalus, found in Muttukadu lagoon.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study reveals that human enteric bacteria MK which is considered as nonpathogenic to fish, may become pathogenic to fish when it harbours this cationic factor. This cationic factor is found to be pathogenic to the fish M. cephalus leading to mortality. It was also found to be pathogenic to mice. Therefore, the shuttling of Ent. cloacae, harbouring cationic factor, between human and fish may be of human health importance.

Enterobacteriaceae

This review summarises the changing epidemiology of resistance to cephalosporins and fluoroquinolones among the Enterobacteriaceae since the 1980s and its potential impact on prescribing choices now and in the immediate future. Whilst multiresistant Enterobacteriaceae are not a novel problem for high-risk hospital units, such as intensive care, the emergence of Escherichia coli co-expressing extended-spectrum beta-lactamases, such as CTX-M types, along with fluoroquinolone resistance in the community is starting to impact in situations where cephalosporins and ciprofloxacin were seen as reliable first-line choices. The reduction in effective options to treat these infections, particularly of the urinary tract and bacteraemia, is likely to result in increased prescribing of carbapenems, thus generating further selective pressure for carbapenemases and other mechanisms of carbapenem resistance in the future.