Risk factors and outcome of levofloxacin-resistant <Emphasis Type="Italic">Elizabethkingia meningoseptica</Emphasis> bacteraemia in adult patients in Taiwan

Elizabethkingia meningoseptica is an emerging nosocomial pathogen associated with high mortality and inherently resistant to many antimicrobial agents. Levofloxacin has been considered as a therapeutic agent based on in vitro susceptibility. We aim to investigate the risk factors and outcomes for levofloxacin-resistant E. meningoseptica bacteraemia. Adult patients with E. meningoseptica bacteraemia were identified retrospectively in a medical centre in Taiwan from January 2011 to July 2015. These strains were identified by the Vitek2 automated system or matrix-assisted laser desorption-ionization time-of-flight mass spectrometry. We compared clinical features and outcomes of patients with levofloxacin-resistant (MIC >2 μg/mL) and levofloxacin-susceptible (MIC ≤2 μg/mL) E. meningoseptica bacteraemia. A total of 93 patients were identified, including 51 (54.8%) with levofloxacin-resistant E. meningoseptica bacteraemia. The APACHE II score (OR, 1.08; 95% CI, 1.02–1.14; p?=?0.008) was the only independent risk factor for levofloxacin-resistant E. meningoseptica bacteraemia. The 14-day mortality for patients with levofloxacin-resistant E. meningoseptica bacteraemia (attributable mortality: 30.7%) was significantly higher than that for patients with the levofloxacin-susceptible strain (56.9% versus 26.2%, p?=?0.003). In the multivariate analysis of risk factors for mortality, appropriate definite antibiotic use was the only factor associated with 14-day survival (OR, 0.11; 95% CI, 0.02–0.55, p?=?0.007). The levofloxacin-resistant strain was borderline significantly associated with mortality (OR, 3.09; 95% CI, 0.88–10.91, p?=?0.079). The early identification of levofloxacin resistance in E. meningoseptica isolates is important to tackle this multi-drug resistance pathogen.     

Characterisation of VIM-2-producing <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> isolates from lower tract respiratory infections in a Spanish hospital

To analyse the antimicrobial phenotype, carbapenem mechanisms, integrons, virulence factors and molecular typing of 164 Pseudomonas aeruginosa isolates recovered from lower tract respiratory samples in a Spanish hospital (1 year) as well as the patients’ clinical data. Susceptibility testing to 12 antipseudomonal agents was determined by microdilution and metallo-beta-lactamase (MBL) phenotype by double disc method. The oprD gene was studied by PCR, sequencing and comparison with P. aeruginosa PAO1 sequence. Detection and characterisation of MBLs, class 1, 2 and 3 integrons, and virulence genes were studied by PCR and sequencing. The prevalence of carbapenem-resistant P. aeruginosa (CRPA) was 26.8%. MBL phenotype was detected in 52.3% CRPA, and all of them were disseminated throughout the intensive care unit. Most of the MBL-carrying patients presented respiratory disease, mechanical ventilation, tracheostomy, bacteraemia, ≥?30 hospitalisation days and previous treatment with carbapenems and/or ≥?3 different antimicrobial families. The bla_VIM-2 gene was the unique MBL encoding gene and was detected inside class 1 integrons. The class 1 integrons detected in 39 strains (23.8%) were associated with aminoglycosides (aadB, aadA1, aadA6, aacA4, aac(3)-I) and carbapenems resistance genes (bla_VIM-2). The aac(3)-I?+?aadA1 and bla_VIM-2 arrangements were the most prevalent ones. Thirty-one different PFGE patterns and 4 STs (ST175, ST235, ST253, ST973) were detected among the 39 intI1-positive isolates, being ST235 the most frequent. CRPA showed a great variety of alterations in oprD gene. The exoU⁺/exoS^? genotype was detected in 82.6% of bla_VIM-2-producing strains (ST235) and the exoU^?/exoS⁺ in the remaining 17.4% (ST973).     

Colistin combination therapy improves microbiologic cure in critically ill patients with multi-drug resistant gram-negative pneumonia

Currently, in vitro synergy with colistin has not translated into improved clinical outcomes. This study aimed to compare colistin combination therapy to colistin monotherapy in critically ill patients with multi-drug resistant gram-negative (MDR-GN) pneumonia. This was a retrospective analysis of critically ill adult patients receiving intravenous colistin for MDR-GN pneumonia comparing colistin combination therapy to colistin monotherapy with a primary endpoint of clinical cure. Combination therapy was defined by administration of another antibiotic to which the MDR-GN pathogen was reported as susceptible or intermediate. Ninety patients were included for evaluation (41 combination therapy and 49 monotherapy). Baseline characteristics were similar between groups. No difference in clinical cure was observed between combination therapy and monotherapy in univariate analysis, nor when adjusted for APACHE II score and time to appropriate antibiotic therapy (57.1 vs. 63.4 %, adjusted OR 1.15, p?=?0.78). Microbiological cure was significantly higher for combination therapy (87 vs. 35.5 %, p?<?0.001). Colistin combination therapy was associated with a significant improvement in microbiological cure, without improvement in clinical cure. Based on the in vitro synergy and improvement in microbiological clearance, colistin combination therapy should be prescribed for MDR-GN pneumonia. Further research is warranted to determine if in vitro synergy with colistin translates into improved clinical outcomes.     

Clinical significance and outcome of <Emphasis Type="Italic">Aeromonas</Emphasis> spp. infections among 204 adult patients

The objectives of this investigation were to analyze the clinical patterns, risk groups, prognostic factors, and mortality of infections caused by Aeromonas spp. This was a retrospective study of adult patients with Aeromonas spp. isolates attended at the Hospital del Mar in Barcelona, Spain, between January 2006 and December 2012. Epidemiological data, antimicrobial susceptibility, clinical patterns, underlying illnesses, type of infection, admission to the intensive care unit (ICU), number of episodes, coinfection, antimicrobial therapy, and evolution were analyzed. A total of 221 clinical samples from 204 patients were positive for Aeromonas spp. The mean age of the patients was 67.6 years. The main clinical form of presentation was gastrointestinal (78.4%). Malignancy was the main risk group in 69 (33.8%) patients, and 48 (23.5%) were previously healthy. Twenty-one patients (10.3%) were admitted to the ICU. Infections were acquired in the hospital in 52.5% of the patients, and 28.9% were polymicrobial. The overall mortality (after 1 year of follow-up from the first positive culture) was 26.5%. Univariate analysis identified an association between increased mortality and the following variables: age ≥80 years, hospitalization, admission to the ICU, malignancy, extraintestinal infection, and appropriate antimicrobial therapy. In the multivariate analysis, age ≥80 years [odds ratio (OR), 4.37 [95% confidence interval (CI), 1.68–11.35; p?=?0.002]], admission to the ICU (OR, 6.59 [95% CI, 2.17–19.99; p?=?0.001]), and malignancy (OR, 3.62 [95% CI, 1.32–9.90; p?=?0.012]) were significantly associated with mortality. Aeromonas infections are mainly gastrointestinal. The 1-year follow-up mortality rate was high. Old age (age?≥80 years), admission to the ICU, and malignancy were identified as independent risk factors for mortality.     

An evaluation of risk factors to predict target concentration non-attainment in critically ill patients prior to empiric β-lactam therapy

To determine whether target concentration non-attainment can be anticipated in critically ill patients prior to initiating empiric β-lactam antibiotic therapy based on readily available clinical factors. Retrospective review of consecutive patients treated with piperacillin or meropenem and who underwent therapeutic drug monitoring (TDM) at St Vincent’s Hospital (Sydney, Australia) between January 2013 and December 2015 was performed. Predefined subgroups were patients who received continuous renal replacement therapy (CRRT) and those who did not (non-CRRT). Potential risk factors were evaluated by correlation with β-lactam antibiotic trough concentrations (C_min) lower than or equal to targeted minimum inhibitory concentration (MIC). Only the first drug concentration after initiation of the antibiotic treatment was included to reflect empirical dose selection. A total of n?=?249 patients (piperacillin, n?=?169; meropenem, n?=?80) were investigated. For non-CRRT patients (n?=?210), multivariate analysis demonstrated the following: male gender (p?=?0.006); younger age (p?=?0.015); prescribed daily antibiotic dose less than 1.5 times the product information recommendations (p?=?0.004); lack of positive microbiology (p?=?0.006); lower overall illness severity (p?=?0.005); and estimated glomerular filtration rate (eGFR) ≥?90 mL/min/1.73 m² (p?<?0.001), to be associated with C_min?≤?MIC. No predictor variable was found to be significantly associated with C_min?≤?MIC for the CRRT cohort. Evaluating the risk of target concentration non-attainment using simple clinical factors is possible at the bedside for non-CRRT patients prior to empiric antibiotic initiation. Clinicians should be wary of selecting doses based on the product information especially when treating younger male patients with apparently ‘normal’ renal function.     

Carbapenemase-producing <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> bloodstream infection in critically ill patients: risk factors and predictors of mortality

A significant increase in carbapenemase-producing Klebsiella pneumoniae (CP-Kp) bacteraemias has been observed worldwide. The objective of the present work was to study the risk factors and predictors of mortality of CP-Kp bacteraemias among critically ill patients. During a 4-year period (2012–3015), a matched 1:2 case-control study was conducted. Klebsiella pneumoniae was identified by Vitek 2 technology. Antibiotic susceptibility was performed by the agar disc diffusion method and Etest. The presence of the bla _KPC, bla _VIM and bla _NDM genes was confirmed by polymerase chain reaction (PCR). Epidemiologic data were collected from the intensive care unit (ICU) computerised database. One hundred and thirty-nine patients who developed a CP-Kp bacteraemia were matched with 278 patients. The majority of isolates (128; 92.1%) carried the bla _KPC gene, seven carried both bla _KPC and bla _VIM, three bla _VIM and one carried bla _NDM. Risk factors for the development of CP-Kp bacteraemia were administration of tigecycline and number of antibiotics administered prior to CP-Kp bacteraemia. Overall, the 30-day mortality was 36.0%. Multivariate analysis revealed septic shock, Simplified Acute Physiology Score II (SAPS II) upon infection onset, adjunctive corticosteroid administration and parenteral nutrition as independent predictors of mortality, while treatment with a combination of appropriate antibiotics was identified as a predictor of good prognosis. Among septic shock patients (n?=?74), Sequential Organ Failure Assessment (SOFA) score upon infection onset, adjunctive corticosteroid administration and strain carrying the bla _KPC gene were independently associated with mortality, while the administration of combination treatment was identified as a predictor of a good prognosis. The administration of tigecycline predisposes to the induction of bacteraemia. Appropriate antibiotic treatment is associated with better survival, while concomitant corticosteroid treatment is associated with mortality.     

Treatment outcome of non-carbapenemase-producing carbapenem-resistant <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> infections: a multicenter study in Taiwan

Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections are associated with high mortality, and experiences with its treatment are usually based on carbapenemase-producing strains. Non-carbapenemase-producing CRKP is of clinical significance, but relevant studies are lacking. This nationwide study aimed to evaluate the outcome of antimicrobial therapy in patients with non-carbapenemase-producing CRKP infections. Patients with non-carbapenemase-producing CRKP infections were enrolled from 16 hospitals during January 2013 to December 2014 in Taiwan. Carbapenem resistance was defined as reduced susceptibility with a minimum inhibitory concentration of ≥2 mg/L for imipenem or meropenem. The resistance mechanisms of CRKP isolates were analyzed, and the clinical data of these patients were collected retrospectively. Independent risk factors of 14-day morality were determined by Cox regression analysis. A total of 99 patients with non-carbapenemase-producing CRKP infections were enrolled, and 14-day mortality was 27.3%. Among 67 patients treated with appropriate antimicrobial therapy, most (n?=?61) patients received monotherapy. The 14-day mortality was lower in patients treated with appropriate monotherapy (21.3%) than in those with inappropriate therapy (37.5%). The multivariate regression model identified monotherapy (hazard ratio [HR], 0.30; 95% confidence interval [CI], 0.13–0.71; P?=?0.005) as protective factor, and APACHE II scores (HR, 1.09; 95% CI, 1.01–1.18; P?=?0.022) as risk factor associated with 14-day mortality. Tigecycline, colistin, and carbapenem were the most commonly used drugs in monotherapy. This study provides evidence supporting the efficacy of monotherapy in the treatment of non-carbapenemase-producing CRKP infections, and provides a future target for antibiotics stewardship for CRKP infection.     

Success of benznidazole chemotherapy in chronic <Emphasis Type="Italic">Trypanosoma cruzi</Emphasis>-infected patients with a sustained negative PCR result

Cure assessment in chronic Trypanosoma cruzi infection is controversial, mainly because of the lack of reliable tests to ensure parasite elimination. Here, we assess the impact of benznidazole therapy on the conventional serology and parasitaemia in chronic Chagas disease. A total of 455 patients with long-term Trypanosoma cruzi infection underwent specific chemotherapy with benznidazole. Their parasitological status was assessed by polymerase chain reaction (PCR) detection of T. cruzi DNA. Drops in the titres of antibody levels were serially measured by indirect immunofluorescence assay (IFI) and chemiluminescent microparticle immunoassay (CMIA). Patients were monitored during the treatment period and for a further 90, 150 and 240 days. Controls were repeated yearly during the 7-year follow-up. The PCR result was negative in all patients between 60-day (n?=?22) and 90-day (n?=?294) controls. Treatment failure was detected in 45 patients and was significantly more frequent in those who did not complete the therapy [12 out of 13 (92 %) vs. 33 out of 442 (7 %)] (p?=?0.0001). A significant drop in serum titres was detected after the first follow-up year in patients with sustained negative PCR results: 2nd year (p?=?0.029 by IFI; p?=?0.002 by CMIA), 5th year (p?=?0.036 by IFI; p?=?0.039 by CMIA) and 6th year (p?=?0.028 by IFI; p?=?0.019 by CMIA). The results point to a beneficial effect of benznidazole and may be the cure of chronic patients who had a consistently negative PCR result throughout the follow-up period.     

New Mutations in Ciprofloxacin Resistant Strains of <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> Isolated from Guilan Province,Northern Iran

Introduction

Pseudomonas aeruginosa (P. aeruginosa) is a gram-negative bacterium that continues to be a major cause of opportunistic nosocomial infections. In P. aeruginosa, several fluoroquinolones resistance mechanisms have been proposed such as mutations in the target enzymes GyrA and ParC and upregulation of efflux pump MexAB-OprM. Fluoroquinolones inhibit the target enzymes DNA gyrase and topoisomerase IV, each comprised of two subunits: GyrA and GyrB, and ParC and ParE, respectively. In addition, fluoroquinolones were blocked by overexpression of MexAB-OprM induced through mutations in the regulatory genes mexR and nalC.

Materials and methods

In this study, 44 P. aeruginosa strains were isolated from different clinical samples of burn and infection from patients in some hospitals and laboratories in Guilan, which were identified by biochemical tests. The antibiotic resistance and susceptibility of strains was determined by Kirby Bauer method and microdilution method, and then PCR-sequencing was carried out to assess mutation in several genes involved in ciprofloxacin resistance.

Results

Of 44 isolates, 14 isolates were fluoroquinolone resistant. All 14 strains were nalidixic acid resistant with MIC = 1024 μg/mL. While ciprofloxacin resistance was showed in resistant isolates with MIC to be 32–1024 μg/mL. PCR-sequencing analysis showed that all 14 fluoroquinolone resistant isolates had one or two mutations in gyrA mutation. Mutations in parC, mexR and nalC were shown in some ciprofloxacin resistant isolates. Moreover, three strains had new mutation in mexR gene (111InsC and 262-263delAG).

Conclusions

It seems that high resistance to ciprofloxacin can simultaneously be the result of mutation in several genes such as topoisomerase enzymes and negative regulatory genes implicated in the expression of efflux pump systems in Guilan Province.

     

<Emphasis Type="Italic">Acinetobacter baumannii</Emphasis> bacteraemia in patients with haematological malignancy: a multicentre retrospective study from the Infection Working Party of Jiangsu Society of Hematology

Acinetobacter baumannii (Ab) bacteraemia in patients with haematological malignancies is fatal but rarely reported. We explored the clinical characteristics, drug resistances and prognostic factors in these patients. This multicentre, retrospective study was conducted at the department of haematology wards of 18 tertiary hospitals in China from January 2014 to June 2015. The total clinical isolates from every source were collected from patients with haematological malignancy. Haematological malignancy patients diagnosed with Ab bacteraemia were analysed. During the study period, 40 patients with Ab bacteraemia were identified, accounting for 2.9% (40/1358) of bacteraemia cases, of which 25 (62.5%) had acute leukaemia (AL) and 27 (67.5%) had neutropaenia. Compared with non-neutropaenic patients, neutropaenic patients showed higher Acute Physiology and Chronic Health Evaluation (APACHE) scores and 30-day mortality rates (p?<?0.05). The in vitro antibiotic susceptibility of Ab to colistin was highest, at 100%, followed by that of tigecycline (91.30%) and amikacin (75.86%). Compared with the patients who had carbapenem-susceptible Ab infections, patients infected with carbapenem-resistant Ab (CRAB) had significantly longer hospital stays and were more likely to have had exposure to carbapenem before bacteraemia (p?<?0.05). The 30-day mortality rate was 32.5%. CRAB, neutropaenia, higher APACHE score, Pitt bacteraemia score and inappropriate initial antimicrobial therapy were significantly associated with 30-day mortality. Multivariable analysis showed that APACHE score and CRAB were independent predictors of 30-day mortality. Haematologic patients with AL and febrile neutropaenia were at high risk of Ab bacteraemia. More attention should be paid to CRAB, which is an independent risk factor for mortality in haematological malignancy patients with Ab bacteraemia.     

The predictor of mortality outcome in adult patients with Ebola virus disease during the 2014–2015 outbreak in Guinea

The purpose of this study was to examine the association of any demographic and clinical factors with mortality outcome among adult patients with Ebola virus disease (EVD) in Guinea. This retrospective observational study analyzed medical records of laboratory confirmed EVD adult patients during the 2014–2015 EVD outbreak in Guinea. The associations between any demographic or clinical variables and mortality outcome of EVD were assessed using univariate and multivariate logistic regression analyses. Of 2,310 EVD adult patients included for analysis, the overall case fatality rate was 68.1%. Univariate analyses identified factors possibly associated with mortality outcome, including patient age (p?<?0.001), history of visiting or close contact with a suspected or confirmed EVD patient (p?=?0.035), and seven clinical symptoms on admission, i.e., fever (p?=?0.003), hiccups (p?<?0.001), vomiting (p?=?0.003), diarrhea (p?<?0.001), cough (p?=?0.001), sore throat (p?=?0.016), and unexplained bleeding (p?=?0.021). The multivariate analysis showed that patient age was independently associated with mortality outcome of EVD (OR?=?1.06; 95%CI?=?1.03–1.09; p?<?0.001), while none the of clinical symptoms on admission were significantly associated with the mortality outcome. Our analysis indicates that older age was the only independent factor associated with death among EVD adult patients in Guinea. This suggests that older EVD patients should receive intensive medical care and be carefully monitored.     

Reduced pro-inflammatory responses to <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> bloodstream infection and low prevalence of enterotoxin genes in isolates from patients on haemodialysis

Patients with end-stage renal failure undergo regular haemodialysis (HD) and often develop episodes of Staphylococcus aureus bloodstream infection (BSI), which can re-occur. However, clinically, patients on HD, with S. aureus BSI, respond well to treatment, rarely developing overt signs of sepsis. We investigated the contributions of bacterial virulence and cytokine responses to the clinical course of S. aureus BSI in HD and non-HD patients. Seventy patients were recruited, including 27 (38.6 %) patients on HD. Isolates were spa-typed and virulence and antimicrobial resistance gene carriage was investigated using DNA microarray analysis. Four inflammatory cytokines, IL-6, RANTES, GROγ and leptin, were measured in patient plasma on the day of diagnosis and after 7 days. There was no significant difference in the prevalence of genotypes or antimicrobial resistance genes in S. aureus isolates from HD compared to non-HD patients. The enterotoxin gene cluster (containing staphylococcal enterotoxins seg, sei, sem, sen, seo and seu) was significantly less prevalent among BSI isolates from HD patients compared to non-HD patients. Comparing inflammatory cytokine response to S. aureus BSI in HD patients to non-HD patients, IL-6 and GROγ were significantly lower (p?=?0.021 and p?=?0.001, respectively) in HD patients compared to other patients on the day of diagnosis and RANTES levels were significantly lower (p?=?0.025) in HD patients on day 7 following diagnosis. Lowered cytokine responses in HD patients and a reduced potential for super-antigen production by infecting isolates may partly explain the favourable clinical responses to episodes of S. aureus BSI in HD patients that we noted clinically.     

The efficacy of the direct clinical intervention for infectious diseases by a pediatric infectious disease specialist in the pediatric ward of a tertiary medical facility without a pediatric antimicrobial stewardship program

Antimicrobial stewardship programs (ASPs) have been introduced in most hospital complexes; however, they are not always useful for pediatric patients. The aim of this study is to investigate the efficacy of direct clinical intervention for infectious diseases by a pediatric infectious disease specialist in a tertiary medical facility without pediatric ASP. This retrospective study included 1,821 patients who were hospitalized in the pediatric ward of a large metropolitan hospital from 2010 to 2015. The clinical course, the use of intravenous antimicrobial agents and the results of a microbiological analysis were compared between the period after the beginning of direct intervention by the specialist (post-intervention period) and the previous period (pre-intervention period). In the post-intervention period, the proportion of the patients who received intravenous antimicrobial agents, the number of antimicrobial agents used for each episode, and the proportion of episodes in which an antimicrobial agent was re-administrated were significantly lower (P?=?0.006, P?=?0.004, P?=?0.036, respectively), and the duration of antimicrobial treatment was significantly shorter (P?<?0.001). In addition, narrower spectrum antimicrobial agents were used, and the incidence of meropenem-sensitive Pseudomonas aeruginosa significantly increased (P?=?0.037) in the post-intervention period. There was no change of mortality between the two periods. Direct clinical intervention by a pediatric infectious diseases specialist is useful for the treatment of infectious diseases in the pediatric ward of a tertiary medical facility without a pediatric ASP. The creation of a pediatric ASP is recommended in hospital complexes.     

Intrapulmonary percussive ventilation improves lung function in cystic fibrosis patients chronically colonized with <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis>: a pilot cross-over study

High levels of shear stress can prevent and disrupt Pseudomonas aeruginosa biofilm formation in vitro. Intrapulmonary percussive ventilation (IPV) could be used to introduce shear stress into the lungs of cystic fibrosis (CF) patients to disrupt biofilms in vivo. We performed a first-of-its-kind pilot clinical study to evaluate short-term IPV therapy at medium (200 bursts per minute, bpm) and high frequency (400 bpm) as compared to autogenic drainage (AD) on lung function and the behavior of P. aeruginosa in the CF lung in four patients who are chronically colonized by P. aeruginosa. A significant difference between the three treatment groups was observed for both the forced expiratory volume in 1 s (FEV1) and the forced vital capacity (FVC) (p?<?0.05). More specifically, IPV at high frequency significantly increased FEV1 and FVC compared to AD (p?<?0.05) and IPV at medium frequency (p?<?0.001). IPV at high frequency enhanced the expression levels of P. aeruginosa planktonic marker genes, which was less pronounced with IPV at medium frequency or AD. In conclusion, IPV at high frequency could potentially alter the behavior of P. aeruginosa in the CF lung and improve lung function. Trial registration: The trail was retrospectively registered at the ISRCTN registry on 6 June 2013, under trial registration number ISRCTN75391385.     

<Emphasis Type="Italic">Mycoplasma hominis</Emphasis> and <Emphasis Type="Italic">Gardnerella vaginalis</Emphasis> display a significant synergistic relationship in bacterial vaginosis

Gardnerella vaginalis plays an important role in bacterial vaginosis (BV,) while the role of genital Mollicutes is less obvious. The diagnosis of BV by use of the current Gram stain Nugent score is also suboptimal for defining the role of Mollicutes that lack a cell wall. Since bacterial load and diversity is an important prerequisite for BV, real-time quantitative polymerase chain reaction (qPCR) assays enable these to be assessed. The purpose of this study was to define the role of genital Mollicutes and potential patterns of synergy with G. vaginalis in women with BV. Vaginal swabs from 130 women categorised by Nugent score as BV (n?=?28), intermediate (n?=?22) and non-BV (n?=?80) were tested against four qPCR TaqMan assays targeting G. vaginalis, Mycoplasma hominis, M. genitalium, Ureaplasma urealyticum and U. parvum. Statistical analyses were used to compare bacterial prevalence and load between the three groups of women. Mycoplasma hominis and G. vaginalis co-infection was significantly more common in BV (60.7 %) compared to intermediate (36.4 %) and non-BV (8.8 %) Nugent scores (p?<?0.001). Significantly higher loads of M. hominis (p?=?0.001) and G. vaginalis (p?<?0.001) were detected in women with BV and the respective loads in M. hominis and G. vaginalis co-infections displayed a significant positive correlation (p?<?0.001; r?=?0.60). No significant associations were seen with the other Mollicutes. The findings strengthen the evidence of a role for M. hominis in BV and a potential synergy with G. vaginalis. This synergy could be an important trigger of the condition and sexual contact the conduit for the transmission of an otherwise commensal bacterium that could initiate it.     

Prevalence and molecular diversity of invasive <Emphasis Type="Italic">Streptococcus dysgalactiae</Emphasis> and <Emphasis Type="Italic">Streptococcus pyogenes</Emphasis> in a German tertiary care medical centre

Prevalence of invasive ß-haemolytic streptococci (BHS) at a tertiary care hospital and molecular diversity of S. pyogenes and S. dysgalactiae was studied. Between 2012 and 2016, all blood culture sets (n?=?55,839), CSF (n?=?8413) and soft tissue (n = 20,926) samples were analysed for BHS positivity using HYBASE software. Molecular profiles of 99 S. pyogenes and S. dysgalactiae were identified by sequencing of M protein genes (emm types) and multiplex PCR typing of 20 other virulence determinants. Streptococci contributed to 6.2% of blood, 10.7% of CSF and 14.5% of soft tissue isolates, being among the most common invasive isolates. The overall rates of invasive S. pyogenes, S. agalactiae, S. dysgalactiae and S. pneumoniae were 2.4, 4.4, 2.1, and 5.3%. Whereas S. pneumoniae was 1.5% more common in CSF samples, BHS isolates were 2-fold and 11-fold higher in bacteraemia and invasive soft tissue infections. Genetic BHS typing revealed wide molecular diversity of invasive and noninvasive group A and group G BHS, whereas one emm-type (stG62647.0) and no other virulence determinants except scpA were detected in invasive group C BHS. BHS were important invasive pathogens, outpacing S. pneumoniae in bacteraemia and invasive soft tissue infections. The incidence of S. dysgalactiae infections was comparable to that of S. pyogenes even with less diversity of molecular virulence. The results of this study emphasise the need for awareness of BHS invasiveness in humans and the need to develop BHS prevention strategies.     

Rapid identification of <Emphasis Type="Italic">Streptococcus pneumoniae</Emphasis> in blood cultures by using the ImmuLex,Slidex and Wellcogen latex agglutination tests and the BinaxNOW antigen test

Rapid identification of Streptococcus pneumoniae in blood culture (BC) bottles is important for early directed antimicrobial therapy in pneumococcal bacteraemia. We evaluated a new latex agglutination (LA) test on BC bottles, the ImmuLex? S. pneumoniae Omni (Statens Serum Institut, Denmark), and compared the performance with the Slidex® pneumo-Kit (bioMérieux, France) and the Wellcogen? S. pneumoniae (Remel, UK) LA tests, as well as the BinaxNOW® S. pneumoniae (Alere, USA) antigen test. The four tests were directly applied on 358 positive BC bottles with Gram-positive cocci in pairs or chains and on 15 negative bottles. Valid test results were recorded in all cases for ImmuLex and BinaxNOW and in 88.5 % (330/373) and 94.1 % (351/373) of cases for Slidex and Wellcogen, respectively. Based on bottles positive for S. pneumoniae by conventional methods, the sensitivity of ImmuLex was 99.6 %, similar to the other tests (range, 99.6–100 %). Based on bottles positive for non-pneumococcal pathogens, the specificity of ImmuLex was 82.6 %, in comparison to 97.6 % for Slidex (p?<?0.01) and 85.4 % for Wellcogen (p?=?ns). The BinaxNOW test had a lower specificity (64.1 %) than any LA test (p?<?0.01). On BC bottles positive for α-haemolytic streptococci, ImmuLex was positive in 12/67 (17.9 %) cases, Slidex in 2/59 (3.4 %) cases, Wellcogen in 11/64 (17.2 %) cases and BinaxNOW in 25/67 (37.3 %) cases. In conclusion, the ImmuLex test provides a valid and sensitive technique for the rapid detection of S. pneumoniae in BC bottles, similar to the other compared methods. However, the specificity was sub-optimal, since the test may cross-react with other Gram-positive bacteria.     

Bloodstream infections caused by <Emphasis Type="Italic">Escherichia coli</Emphasis> producing AmpC β-lactamases: epidemiology and clinical features

The aim of the study was to investigate the epidemiology and clinical features of bloodstream infections due to Escherichia coli producing AmpC β-lactamases (AmpC-Ec-BSI). In a multi-centre case–control study, all third-generation-cephalosporin-resistant Escherichia coli BSI (3GC-Ec-BSI) isolates were analysed. Acquired bla _AmpC (bla _ac-AmpC) detection was done by polymerase chain reaction (PCR) and sequencing. Chromosomal bla _AmpC (bla _c-AmpC) expression was quantified by real-time PCR. Cases were patients with AmpC-Ec-BSI. Controls were patients with cephalosporin-susceptible E. coli BSI, matched 1:1 by sex and age. Demographics, comorbidities, intrinsic and extrinsic risk factors for antimicrobial resistance, clinical presentation and outcomes were investigated. Among 841 E. coli BSI, 17 were caused by AmpC-Ec (2 %). Eleven isolates (58.8 %) had bla _ac-AmpC and six were bla _c-AmpC overproducers. The mean age of cases was 66.2 years and 71 % were men. Cases were more frequently healthcare-related (82 vs. 52 % controls, p?<?0.05) and presented more intrinsic and extrinsic risk factors. At least one risk factor was present in 94.1 % of cases vs. 41.7 % of controls (p?=?0.002). Severity and length of stay (LOS) were higher among cases (mean Pitt Score 2.6 vs. 0.38 in controls, p?=?0.03; LOS 17.5 days vs. 6 in controls, p?=?0.02). Inappropriate empirical therapy (IET) was administered to 70.6 % of cases and 23.5 % of controls (p?<?0.003). No differences were found in terms of cure rate at the 14th day and mortality. Bloodstream infections due to AmpC-Ec (mostly plasmid-mediated) are infrequent in our area. AmpC-Ec-BSI affects mainly patients with intrinsic risk factors and those with previous antibiotic exposure. A high proportion received IET.     

Prevalence and molecular characterization of class 1 integrons among clinical isolates of <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> in Northwest of Iran

Introduction

Integrons are introduced as the most common mechanism for resistance gene dissemination in Pseudomonas aeruginosa.

Aims and tasks

The purpose of the present study was to determine the diversity of the gene cassettes carried with class 1 integrons in clinical isolates of Pseudomonas aeruginosa.

Methods and results

One hundred clinical isolates of Pseudomonas aeruginosa from four hospitals in Northwest of Iran were investigated for antimicrobial susceptibility, presence of class 1 integrons and associated resistance gene cassettes. Seventy-one percent of isolates were multidrug resistant (MDR) and colistin was the most effective antibiotic in this study. Sixty-six isolates (66%) were contained class 1 integrons which all of them carried gene cassettes. There was a strong correlation between integron presence and multidrug resistance phenotype (p < 0.05). Amplification of the internal variable regions of class 1 integrons revealed 10 different arrays ranging in size from 0.6 to 3.5 kb. DNA sequencing analysis of class 1 integrons revealed the presence of several gene cassettes associated with resistance to aminoglycosides (aac and aad), β-lactams (bla _OXA), chloramphenicol (cmlA and catB), hypothetical gene cassette encoding a hypothetical protein and an open reading frame with unknown function (orfD). The most prevalent gene cassette found within class 1 integrons was aadB (68.18%), followed by aacA4 (48.48%). To the best of our knowledge, some of the gene cassettes arrays such as aac(3)-Ic-aacA5-cmlA5 and aacA5-aadA1-cmlA5 were first identified in this study. Hospital ward was demonstrated as significant risk factors for the acquisition of class 1 integrons harboring isolates in this study (P < 0.05).

Conclusions

Most of gene cassette arrays in this study are reported for the first time in Iran. These show the role of integrons in dissemination of resistance genes among clinical isolates of P. aeruginosa.

     

Haematological and acute-phase response of dogs with experimental skin <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> infection to treatment with antibiotic and parthenolide

Changes in white blood cells, leukogram patterns, the positive acute-phase protein (APP) fibrinogen and negative APPs (albumin and arylesterase) were monitored to evaluate their potential as sensitive indicators throughout the course of therapy in canine skin Pseudomonas aeruginosa infection. The study was performed on 15 male mixed-breed dogs, divided in three groups of 5 dogs each. Dogs from group A were injected subcutaneously with P. aeruginosa bacterial culture (1?×?10⁸ CFU/mL) at a dose of 0.3 mL/kg and treated with enrofloxacin (5 mg/kg, s.c.) on post infection hour 48 for 10 consecutive days. Dogs from group B were infected and treated with a combination of enrofloxacin (at above-mentioned dose and intervals) and parthenolide (feverfew extract 90 mg, 0.7 % parthenolide). The schedule consisted of daily oral intake of two capsules of feverfew beginning on post infection hour 4 and continued for 6 days. The control group C included healthy dogs, injected s.c. with 0.3 mL/kg physiological saline. The haematological indices and APPs were assayed before infection and on 4th, 24th, 48th and 72nd hours and on 7th, 10th and 14th days after infection. Infected and antibiotic-treated dogs responded with significant leukocytosis, left shift, eosinopaenia and lymphopaenia between hours 24 and 72. In this group, fibrinogen increased substantially by post infection hours 24 (p?<?0.01 vs 0 h; p?<?0.05 vs group C), 48 (p?<?0.001 vs 0 h; p?<?0.05 vs group C) and 72 (p?<?0.001 vs 0 h; p?<?0.01 vs group C) while albumin reduction was marked by hours 48 (p?<?0.05 vs 0 h) and 72 (p?<?0.05 vs 0 h; p?<?0.001 vs group C) and day 7 (p?<?0.01 vs 0 h; p?<?0.001 vs group C). The combination of enrofloxacin and parthenolide modified, at a significant extent, the deviations in studied parameters except for eosinophil percentage, which persisted low.