- Volume 65, Issue 2, 2016

To determine the predominant genotype of the varicella-zoster virus (VZV) in suburban Shanghai Municipal Province, specimens were collected from the lesions of 95 outpatients clinically diagnosed with varicella or herpes zoster. Of these, 69 patients (72.6 %) were positive for VZV DNA. The 69 isolates were all genotyped as the genotype J1/clade 2. Based on sequencing of the 447 bp sequence in ORF22, 66 isolates were identified as genotype J/clade 2 strains and three were identified as type M2/clade 4 strains. To confirm the classification of these three strains, we determined the presence of 27 single-nucleotide polymorphisms (SNPs) and found that isolates 1270/1450 shared seven SNPs that differed from those of clade 2, in which three SNPs were unique to clade 3 and another three were unique to clade 4. Isolate 1456 had two markers of clade 4 that differed from clade 2. The phylogenetic tree showed that our isolates clustered primarily with clade 2 and that the three M2/J1 strains clustered between clades 2 and 4. It is likely that isolates 1270/1450/1446 may represent a new subclade of either clade 2 or 4, or some recombinant events. In addition, our isolates were WT strains. We also observed significant inter-strain variations.

Over a period of 3 years' study (2012–2014), a total of 518 faecal samples were collected and cultured to isolate Escherichia coli. Of these, 338 (65.3 %) E. coli isolates were recovered from infants, and 142/338 (42 %) were multidrug-resistant (MDR) to ≥ 3 drug classes using the antimicrobial susceptibility disc diffusion method. A total of 125/142 (88 %) of E. coli isolates were extended-spectrum β-lactamase (ESBL) producers. blaCTX-M-15 types were observed in 80/125 (64 %) of the isolates, and 60/80 (75 %) were positive for blaCTX-M-15. Out of 338 E. coli isolates, 9 (2.6 %) were positive for ST131/O25b clone and each isolate was associated with several plasmids of different sizes (1–21.2 kb). The identities of these nine isolates were confirmed by sequencing for presence of pabB (347 bp) and trpA (427 bp) genes. This study demonstrates low prevalence rate of the highly virulent E. coli ST131 clone producing blaCTX-M-15 in the intestines of Jordanian infants.

The reported incidence of Legionnaires' disease caused by Legionella longbeachae has increased since 2008 in Scotland. While microbiological and epidemiological studies have identified exposure to growing media as a risk factor for infection, little is known about the differences regarding disease risk factors, clinical features and outcomes of infection with L. longbeachae when compared with L. pneumophila. A nested case–case study was performed comparing 12 L. longbeachae cases with 25 confirmed L. pneumophila cases. Fewer L. longbeachae infected patients reported being smokers [27 % (95 % CI 2–52 %) vs. 68 % (95 % CI 50–86 %), P = 0.034] but more L. longbeachae patients experienced breathlessness [67 % (95 % CI 40–94 %) vs. 28 % (95 % CI 10–46 %), P = 0.036]. Significantly more L. longbeachae-infected patients received treatment in intensive care [50 % (95 % CI 22–78 %) vs. 12 % (95 % CI 0–25 %), P = 0.036]. However, the differences in diagnostic methods between the two groups may have led to only the most severe cases of L. longbeachae being captured by the surveillance system. No differences were observed in any of the other pre-hospital symptoms assessed. Our results highlight the similarity of Legionnaires' disease caused by L. pneumophila and L. longbeachae, and reinforce the importance of diagnostic tools other than the urinary antigen assays for the detection of non-L. pneumophila species. Unfortunately, cases of community-acquired pneumonia caused by Legionella species will continue to be underdiagnosed unless routine testing criteria changes.

Clostridium difficile is the most frequently identified enteric pathogen in patients with nosocomial antibiotic-associated diarrhoea and pseudomembranous colitis. Several clinically isolated C. difficile strains are resistant to antibiotics other than metronidazole and vancomycin. Recently, bacteriocins of lactic acid bacteria have been proposed as an alternative or complementary treatment. The aim of this study was to investigate the inhibitory effect of nisin, a bacteriocin produced by several strains of Lactococcus lactis, against clinical isolates of C. difficile. Nisin Z obtained from culture of L. lactis subsp. lactis biovar. diacetylactis was tested along with commercial nisin A. The effect of nisin A on C. difficile spores was also examined. Nisin A and Z both inhibited the growth of all C. difficile isolates, and MICs were estimated at 6.2 μg ml− 1 for nisin Z and 0.8 μg ml− 1 for nisin A. In addition, C. difficile spores were also susceptible to nisin A (25.6 μg ml− 1), which reduced spore viability by 40–50 %. These results suggested that nisin and hence nisin-producing Lactococcus strains could be used to treat C. difficile-associated diarrhoea.

This study evaluated the bactericidal effect of Er:YAG laser radiation combined with sodium hypochlorite (NaOCl) irrigation in the treatment of Enterococcus faecalis deep inside dentinal tubules. The Er:YAG laser was activated, respectively, at 0.3, 0.5 and 1.0 W for either 20 or 30 s; 52.5 g l− 1 NaOCl and normal saline were used for the control groups. Root canals before and after treatments were examined using scanning electron microscopy (SEM). Bacterial reductions both on the root canal walls and at 100, 200, 300, 400 and 500 μm inside the dentinal tubules were analysed using a one-way analysis of variance. SEM results showed that the Er:YAG laser combined with NaOCl disinfected the dentinal tubules from 200 to over 500 μm depth as irradiation power and time increased. This combination killed significantly more bacteria than both the negative control group at each level tested and the positive control group at 300, 400 and 500 μm inside the dentinal tubules. It reached 100 % in all experimental groups, both on the root canal walls and at 100 and 200 μm inside the dentinal tubules. However, at 300, 400 and 500 μm inside the dentinal tubules, only the groups treated with 0.5 and 1.0 W for 30s exhibited no bacterial growth. Of the two groups in which no bacteria were detected at all tested depths, Er:YAG laser irradiation at 0.5 W for 30 s combined with NaOCl irrigation was preferable because of the lower emission power and shorter irradiation time, and may serve as a new option for effective root canal disinfection.

Broad-spectrum antimicrobials are needed to effectively treat patients infected in the event of a pandemic or intentional release of a pathogen prior to confirmation of the pathogen's identity. Engineered cationic antimicrobial peptides (eCAPs) display activity against a number of bacterial pathogens including multi-drug-resistant strains. Two lead eCAPs, WLBU2 and WR12, were compared with human cathelicidin (LL-37) against three highly pathogenic bacteria: Francisella tularensis, Yersinia pestis and Burkholderia pseudomallei. Both WLBU2 and WR12 demonstrated bactericidal activity greater than that of LL-37, particularly against F. tularensis and Y. pestis. Only WLBU2 had bactericidal activity against B. pseudomallei. WLBU2, WR12 and LL-37 were all able to inhibit the growth of the three bacteria in vitro. Because these bacteria can be facultative intracellular pathogens, preferentially infecting macrophages and dendritic cells, we evaluated the activity of WLBU2 against F. tularensis in an ex vivo infection model with J774 cells, a mouse macrophage cell line. In that model WLBU2 was able to achieve greater than 50 % killing of F. tularensis at a concentration of 12.5 μM. These data show the therapeutic potential of eCAPs, particularly WLBU2, as a broad-spectrum antimicrobial for treating highly pathogenic bacterial infections.

A piperacillin/tazobactam (PT) restriction was initiated at our institution on 15 July 2012 requiring clinical pharmacy or infectious diseases approval for durations exceeding 72 h. A retrospective review was undertaken to determine whether this restriction decreased PT usage and/or rates of acute renal failure (ARF) (defined as a 50 % increase or 0.5 mg dl− 1 increase in serum creatinine from baseline). Patients prescribed at least 1 day of PT with a creatinine clearance of ≥ 39 ml min− 1 at the time of initiation in the 3 months prior to the restriction were compared with patients in the 5 months after restriction implementation. Overall, 115 unique patients were included in the pre-implementation group and compared with 117 unique patients in the post-implementation group. The pre-implementation group received a mean of 5.22 days of PT, compared with 4.71 days in the post-implementation group (P = 0.224). Ten per cent (12/115) of patients in the pre-implementation group developed ARF compared with 9.17 % (11/120) of patients in the post-implementation group (P = 0.0309). Ninety-five patients in the pre-implementation group and 91 in the post-implementation group received combination therapy with vancomycin. ARF occurred in 11.6 % (11/95) of those in the pre-implementation group and 12.1 % (11/91) in the post-implementation (P>0.05). Overall, 11.8 % (22/186) of patients who received therapy with PT and vancomycin developed ARF, compared with 1.7 % (1/56) who received PT monotherapy (P < 0.0001). This restriction resulted in a numeric reduction in the number of PT days in the post-implementation group and a significant reduction in the rate of ARF.