Anne Limelette

Fluoroquinolone Resistance Mechanisms and population structure of Enterobacter cloacae non-susceptible to Ertapenem in North-Eastern France.

Fluoroquinolone (FQ) agents are a potential resort to treat infection due to Enterobacteriaceae producing extended spectrum β-lactamase and susceptible to FQ. In a context of increase of non-susceptibility to carbapenems among Enterobacteriaceae, we characterized FQ resistance mechanisms in 75 Enterobacter cloacae isolates non-susceptible to ertapenem in North-Eastern France in 2012 and describe the population structure by pulsed field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Among them, 14.7% (12/75) carried a carbapenemase-encoding gene. Except one isolate producing VIM-1, the carbapenemase-producing isolates carried the well-known IncL/M pOXA48a plasmid. Most of the isolates (59/75) harbored at least a FQ-R determinant. qnr genes were predominant (40%, 30/75). The MLST study revealed that E. cloacae isolates’ clonality was wide [24 different sequence types (STs)]. The more widespread STs were ST74, ST101, ST110, ST114, and ST133. Carbapenem MICs were higher for E. cloacae ST74 than for other E. cloacae isolates. Plasmid-mediated quinolone resistance determinants were more often observed in E. cloacae ST74 isolates. These findings showed that (i) pOXA-48a is spreading in North-Eastern France, (ii) qnr is preponderant in E. cloacae, (iii) E. cloacae comprised a large amount of lineages spreading in North-Eastern France, and (iv) FQ as an alternative to β-lactams to treat ertapenem non-susceptible Enterobacteriaceae are compromised.

First report of nosocomial infection caused by Klebsiella pneumoniae ST147 producing OXA-48 and VEB-8 β-lactamases in Tunisia.

The aim of this study was to determine the origin of virulence and multiresistance of a Klebsiella pneumoniae isolate from an abdominal wound infection of a patient with a gunshot injury in the thoracoabdominal region. The isolate was identified using biochemical tests and Phoenix™ automated system and was confirmed by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). MICs of each antibiotic were determined by Etest. Screening for carbapenemase production was performed by the modified Hodge test and was confirmed by PCR amplification. Virulence factors were also studied. Plasmid replicon typing was used to classify Incompatibility (Inc) plasmids harbouring the resistance genes. The transferability of each plasmid was determined by conjugation using Escherichia coli J53. Finally, multilocus sequence typing (MLST) was performed to determine the ST of the strain. The bacterial isolate was identified as K. pneumoniae and was named KPM2, carrying entB, ybtS, mrkD and ycfM virulence genes, but it did not overexpress OqxAB. Isolate KPM2 belonged to ST147 and was classified as resistant to all of the tested antibiotics with MICs above the clinical breakpoints. These resistances were due to production of OXA-48, CMY-2, TEM-1, CTX-M-15 and VEB-8 β-lactamases. Genetic and molecular studies showed that blaOXA-48 was embedded in transposon Tn1999.2 and was carried by a conjugative IncL/M plasmid of ca. 60kb; blaVEB-8 was harboured on a conjugative IncA/C plasmid of ca. 120kb. This study confirmed that the resistance conferred by OXA-48 and VEB-8 contributed to the failure of antibiotic treatment and consequently death of the patient.

Factors associated with carriage of carbapenem-non-susceptible Enterobacteriaceaein North-Eastern France and outcomes of infected patients

Background Carbapenems are frequently used as a last resort to treat infections caused by multidrug-resistant Gram-negative organisms, thus carbapenem-non-susceptible Enterobacteriaceae (CNSE) is an emerging health threat. Objectives To assess risk factors and outcomes of CNSE carriage. Patients and methods We conducted a matched case-control study in six hospitals in North-Eastern France. The controls were patients harbouring carbapenem-susceptible Enterobacteriaceae. Fifty-five cases and 110 controls were included. Results Most of the CNSE isolates were Enterobacter cloacae and Klebsiella pneumoniae . Carbapenemase production was observed in 40% of isolates and they produced OXA-48 only. CNSE carriage was significantly associated with recent antibiotic use ( P =  0.014), particularly carbapenems ( P =  0.03) and fluoroquinolones ( P =  0.016). A multivariate analysis using conditional logistic regression showed that the presence of concomitant infection(s) (OR: 9.83; 95% CI 3.04-21.39, P =  0.0031), nosocomial infections (OR: 7.84; 95% CI 2.00-12.54, P  =   0.0063) and a high age (OR: 1.07; 95% CI 1.01-1.06, P =  0.038) were independently associated with CNSE carriage. Moreover, patients infected with CNSE had worse outcomes: fewer resolved infections at 1 month ( P =  0.02), and they had a higher mortality rate ( P =  0.0004) and longer hospital stays ( P =  0.02). Conclusions We identified three independent risk factors for CNSE carriage as well as worse outcomes in infected patients in North-Eastern France. This highlights the importance of early detection of CNSE and the need for antimicrobial therapy re-evaluation after bacteriological analysis has been performed.

Macroscopic amoxicillin crystalluria.

A 62-year-old woman was referred to our hospital in September, 2013, with fever, arthralgia, and dyspnoea lasting for 6 days. Her medical history was uneventful apart from hypertension and active tobacco use. Her glomerular fi ltration rate at admission was 82 mL/min per 1·73 m2 (normal range ≥90 mL/min per 1·73 m2). Blood cultures on admission grew Strepto coccus agalactiae and acute aortic infective endocarditis was rapidly diagnosed with transoesophageal echocardiography. She was immediately started on highdose intravenous amoxicillin (200 mg/kg per day) with intravenous gentamicin (240 mg once-daily). After 4 days, we noticed cloudy urine, with a thin granular appearance (fi gure). Her urine pH was 5·5. Direct examination of the urine showed amoxicillin crystalluria with large, typically aggregated needle-shaped crystals (fi gure) that were birefringent under polarised light microscopy. Her clinical condition worsened with oliguria, acute renal failure, and pulmonary oedema within 24 h. An aortic ring abscess was evident on a second echocardiography. After emergency valve replacement surgery and renal replacement therapy, she recovered well and was discharged home in October, 2013, without further renal replacement therapy, and with improving renal function. Her last glomerular fi ltration rate was 45 mL/min per 1·73 m2 in March, 2014. At last follow-up, in September, 2014, the patient was asymptomatic. Amoxicillin is known to cause urine crystallisation, although its incidence is unknown. Amoxicillin crystalluria usually occurs with high-dose amoxicillin therapy, in urines that have a low pH and are highdensity (mainly due to insuffi cient fl uid intakes). Amoxicillin crystalluria can be microscopic or macroscopic. The typical microscopic appearance described here is usually suffi cient for diagnosis in a compatible context but the amoxicillin composition of these crystals can be confi rmed by infrared spectroscopy if needed. Amoxicillin crystalluria can be asymptomatic or can be responsible for haematuria or acute renal failure attributable to intratubular precipitation or urinary tract obstruction. In our patient, acute renal failure was multifactorial, but we speculate that amoxicillin crystalluria could have played a part. Physicians should be aware of such a complication of amoxicillin because high intravenous doses are frequently prescribed worldwide and because urine alkalinisation and increased fl uid intake might prevent crystalluria.

[Investigation of the sudden infant death syndrome: a multidisciplinary approach is required].

The concept of sudden infant death syndrome (SIDS) is defined as the sudden, unexpected death of an infant less than a year old which remains unexplained after in-depth investigations comprising a complete autopsy, biological analyses, and a clinical examination of the circumstances surrounding the death. This definition underlines the importance of finding the cause of this disease in order to improve preventative measures to reduce the number of deaths due to sudden infant death syndrome. Among the causes of SIDS, pediatric infectious diseases may be neglected and must be systematically sought after. We report upon a SIDS death case of a four and a half month-old that occurred during his sleep. Following the absence of an evident cause of death a scientific autopsy was performed. The histological examination of pulmonary tissue revealed broncolitic lesions associated with numerous micro-abscesses. The post mortem microbiological analyses revealed evidence of an infection by the respiratory syncytial virus complicated by a bacterial infection due to Haemophilus influenzae. The case underlines the necessity of a multidisciplinary approach to researching SIDS, involving both clinicians and biologists, in order to determine the causes of these deaths.

Infection systémique à Erysipelothrix rhusiopathiae sans endocardite soulignant les difficultés du diagnostic bactériologiqueCas clinique et revue de la littérature

Erysipelothrix rhusiopathiae is mostly isolated in swine causing erysipelas. Human invasive infections due to E. rhusiopathiae remain poorly described and interestingly bacteraemia associated with endocarditis are a source of ineffective empirical antibiotherapy. We report a case of sepsis without endocarditis due to E. rhusiopathiae and a review of the literature.

Fatal case of hemolytic-uremic syndrome in an adult due to a rare serogroup O91 Entero hemorrhagic Escherichia coli associated with a Clostridium difficile infection. More than meets the eye

Hemolytic-uremic syndrome due to enterohemorrhagic Escherichia coli, belonging to serogroup O91 has rarely been described. We report here a case of post-diarrheal HUS due to EHEC O91 in an elderly patient for whom diagnosis was delayed given a previously diagnosed C. difficile infection. This case highlights the usefulness of Shiga-toxin detection.

Amoxicillin-tolerant Pasteurella multocida strain isolated from chronic dermohypodermitis after suboptimal exposure to amoxicillin is not associated with reduced growth rate

Pasteurella multocida is rarely observed in human chronic infections. A Pasteurella multocida strain was isolated from a skin biopsy of chronic dermohypodermitis in a 21-year-old woman without an immunocompromised state. As this strain was viable one month after a cat scratch despite treatment by amoxicillin-clavulanic acid, we compared this strains growth rate, amoxicillin Minimal Inhibitory and Bactericidal Concentrations (MIC and MBC), resistance to serum and ability to activate neutrophil granulocytes with those of control strains isolated during acute infections in humans without previous antibiotics exposure. This particular strain was not more resistant to serum and did not induce a lower phagocytic activity than control strains. It did not grow more slowly than control strains even after suboptimal exposure to amoxicillin. This particular strain was tolerant to amoxicillin but tolerance did not appear sufficient alone for the induction of a chronic infection in a host without an immunocompromised state.