Low sub-minimal inhibitory concentrations of antibiotics generate new types of resistance

Antibiotic resistance is a major threat to modern medicine. Routes of transmission of resistant bacteria are complex and include spread between humans, between humans and animals, between animals and to humans and animals via the environment. Recent findings have shown that resistant bacteria can be selectively enriched even at antibiotic concentrations several hundred-fold lower than previously expected, such as those found in sewage water. In addition, these low concentrations can select for high level resistant bacteria with very low fitness cost in contrast to resistant bacteria selected at high concentrations such as during antibiotic treatment of patients. This calls for action to determine what concentrations and combinations of antibiotics that can be considered safe in waste water and ensure proper measures to reduce the antropogenic contamination with antibiotics.     

Assessment of the contamination potentials of some foodborne bacteria in biofilms for food products

ObjectiveTo assess biofilms formed by different bacterial strains on glass slides, and changes in biofilm mass and biofilm-associated cell populations after brief contacts between biofilms and either media agar or food products.MethodsTwo Listeria monocytogenes and Escherichia coli (E. coli) strains and a single Staphylococcus aureus (S. aureus) strain were inoculated separately in tryptic soy broth containing glass coupons incubated for 24, 48 or 72 h at 37 °C. The biofilms formed by individual bacterial strains and biofilm-associated cell populations were determined. Biofilms were subsequently allowed to have brief contacts (1-3 times), through gentle touching, with either agar, meat or soft white cheese (2 cm³). Changes in biofilm mass on glass slides and cell populations embedded in biofilms were quantified.ResultsA nonpathogenic E. coli formed more biofilms than an E. coli O157:H7 strain. Biofilms formed by S. aureus and Listeria monocytogenes were essentially similar. The biofilm mass increased as incubation time increased within 48 h of incubation and was not positively correlated with cellulose production. Biofilm mass at 48 and 72 h of incubation was not significantly different. More frequent contacts with agar or foods did not remove more biofilms or biofilm-associated cells from glass slides. More S. aureus biofilms were removed followed by Listeria and E. coli biofilms. Mean contamination of agar or food models was 0.00 to 7.65 log CFU/cm². Greater contaminations in cell populations were observed with S. aureus and Listeria biofilms.ConclusionsThe results provide a clearer assessment of contaminating potential of foods that comes in contact with them.     

The spontaneous decay and persistence of mental contamination: An experimental analysis

Background and objectives

It has recently been identified that feelings of contamination can arise in the absence of physical contact with a stimulus. This concept, known as ‘mental contamination’ has particular relevance to Obsessive Compulsive Disorder in which compulsive cleaning is a common symptom presentation. Experimental studies have begun to examine the psychopathology of mental contamination. The aims of the two experiments reported here were to explore the evocation and spontaneous decay of mental contamination.

Methods

In Experiment 1, a variant of the autobiographical memory task was used in which 40 non-clinical participants were asked to recall autobiographical memories associated with betrayal, harm, humiliation and violation of moral standards. In Experiment 2, 60 participants with moderate levels of mental contamination were asked to complete five short tasks designed to induce mental contamination, including recalling unwanted memories and images.

Results

In both experiments, participants reported significant increases in mental contamination, anxiety, urges to wash and actual washing behaviour. In experiment 1, the effect of the induction decayed spontaneously. Experiment 2 found that re-evoking contamination and repeated washing led to the persistence of mental contamination.

Limitations

The studies were conducted on non-clinical samples.

Conclusions

These findings demonstrated that repeated triggers may be causally connected to the maintenance of mental contamination fears in non-clinical samples.     

Epidemiologic characteristics of resistant microorganisms present in reserves from an intensive care unit

In this study, significant contamination in the intensive care unit environment was observed (P < .004). Sampling of inanimate surfaces and equipment found vancomycin-resistant Enterococcus faecalis, ciprofloxacin-resistant Staphylococcus aureus and S epidermidis, and multiresistant Acinetobacter baumannii with similarities (60%-80%) to blood culture isolates.     

Effect of water contamination on the shear bond strength of self-ligating brackets

PurposeThe aim of the present study is to evaluate the effect of water contamination on the shear bond strength (SBS) and adhesive remnant index (ARI) score of self-ligating brackets.Materials and methodsOne conventional bracket and three different self-ligating brackets were bonded onto 160 bovine permanent mandibular incisors, divided randomly into 8 groups. For each type of bracket, 20 samples were bonded on dry enamel and 20 after water contamination. After 24 h, all specimens were tested for SBS using an Instron Universal Testing Machine, and ARI scores were evaluated.ResultsAll groups showed clinically adequate SBSs. Quick brackets bonded onto dry enamel showed significantly higher SBSs than all other groups tested, whereas the lowest shear strength values were recorded for Step, Quick, and Damon 3MX brackets bonded onto contaminated enamel and for Damon 3MX onto dry enamel. Frequency distribution of ARI Scores showed a prevalence of ARI “2” and “3” for all the groups tested.ConclusionsWater contamination reduces the SBS of self-ligating brackets, but significant differences have been found only for Quick brackets. All groups showed a significant higher frequency of ARI Score of “2” and “3”.     

Hand Hygiene among Anesthesiologists and Microorganisms Contamination in Anesthesia Environments: A Single-Center Observational Study

ObjectiveTo investigate the baseline levels of microorganisms' growth on the hands of anesthesiologists and in the anesthesia environment at a cancer hospital.MethodsThis study performed in nine operating rooms and among 25 anesthesiologists at a cancer hospital. Sampling of the hands of anesthesiologists and the anesthesia environment was performed at a ready-to-use operating room before patient contact began and after decontamination.ResultsMicroorganisms' growth results showed that 20% (5/25) of anesthesiologists' hands carried microorganisms (> 10 CFU/cm²) before patient contact began. Female anesthesiologists performed hand hygiene better than did their male counterparts, with fewer CFUs (P = 0.0069) and fewer species (P = 0.0202). Our study also found that 55.6% (5/9) of ready-to-use operating rooms carried microorganisms (> 5 CFU/cm²). Microorganisms regrowth began quickly (1 hour) after disinfection, and increased gradually over time, reaching the threshold at 4 hours after disinfection. Staphylococcus aureus was isolated from the hands of 20% (5/25) of anesthesiologists and 33.3% (3/9) of operating rooms.ConclusionOur study indicates that male anesthesiologists need to pay more attention to the standard operating procedures and effect evaluation of hand hygiene, daily cleaning rate of the operating room may be insufficient, and we would suggest that there should be a repeat cleaning every four hours.     

The Survey ofCronobacterspp. (formerlyEnterbacter sakazakii) in Infant and Follow-up Powdered Formula in China in 2012

ObjectiveTo determineCronobacterspp.contamination in infant and follow-up powdered formula in China. MethodsAll of 2282 samples were collected from theretailmarkets in China from January 2012 to December 2012, and analyzed forCronobacter spp.by theChineseNationalFood Safety Standard. Characterization of the isolates was analyzed by pulsed-field gel electrophoresis (PFGE) withXbaI and SpeI restriction enzymes. ResultsCronobacterspp. strains were isolated from 25 samples, and the positive rates ininfant powdered formulas and follow-up powdered formulas were 0.90% (10/1011) and 1.18% (15/1271), respectively. Analysis of variable data regarding different purchasing store formats, seasonality, and production locations as well as comparison of infant versus follow-up formulas did not reveal statistically significant factors. During the sampling period, one of six surveillance zones did exhibit a statistically significant trend towards higher positive rate. PFGE characterization ofCronobacterspp.to elucidate genetic diversity revealed only three pairs ofCronobacterspp.out of 25 having the same PFGE patterns. ConclusionThe current investigation indicated a lower positive rate ofCronobacterspp.in the powdered formula in China.This evidence suggested contamination originating from multiple different sources during the manufacturing process.     

Vinyl bag cover method to avoid droplet-containing aerosol escape from endoscopic forceps channel caps during COVID-19 pandemic (with Video 1 and Video 2)

Endoscopists are at high risk of allowing transmission of coronavirus disease 2019 (COVID-19) during gastrointestinal endoscopy (GIE) procedures under pandemic conditions. The main avenues of droplet-containing aerosol generated during GIE are the mouth, anus, and endoscopic forceps channel. Although the usefulness of personal protective equipment for preventing COVID-19 dissemination has been well reported, measures to address infected aerosol escaping during endoscopic forceps use have been neglected. Pathogen-contaminated aerosol from the endoscopic forceps channel, leading into the gastrointestinal lumen, has been confirmed and is a highly problematic source of infection. We developed a technique that entails covering the forceps entry/exit hole with a vinyl bag, thereby preventing contamination of the endoscopy room by the infected aerosol that escapes from this hole. The technique can be used in daily clinical endoscopic practice. Furthermore, this shielding technique is useful for all patients who undergo GIE, regardless of the purpose of the procedure such as for making a diagnosis, administering therapy, or in an urgent situation. In this letter, we introduce our novel, easily performed, inexpensive method of infection prevention by disallowing infected aerosol to escape from a COVID-19-infected patient into the air during a procedure that requires the use of endoscopic forceps.     

“I feel your disgust and relief”: can the action understanding system (mirror neuron system) be recruited to induce disgust and relief from contamination vicariously,in individuals with obsessive–compulsive disorder symptoms?

Research has shown that brain regions mediating disgust (e.g., the insula) become activated when viewing others’ disgust, a response mediated, perhaps by the mirror neuron system or the Theory of Mind module. In a novel behavioral experiment, we explore vicarious disgust and relief, in individuals with obsessive–compulsive disorder (OCD) symptoms. Participants (N = 10) provided disgust ratings to self-contamination or watching the contamination of an experimenter; and to the experimenter washing his own hands after the subjects had been contaminated. To our surprise, we found that subjects experienced disgust from merely watching the experimenter contaminating himself. More intriguingly, after subjects had contaminated themselves, they obtained relief from merely watching the experimenter washing his own hands; even while recognizing the logical absurdity of this. The result is counterintuitive since neither the subjects nor anyone else would have predicted this. These preliminary findings – if confirmed in placebo-controlled studies – might pave the way toward novel therapeutic approaches for OCD.