Frameshift mutation (690delG) in cpxA contributes to the extensive drug resistance of a Serratia marcescens clinical isolate.

OBJECTIVES: To identify the genetic change responsible for resistance to penicillins, extended-spectrum cephalosporins (ESCs), aminoglycosides and ciprofloxacin in a Serratia marcescens clinical isolate recovered from a pancreatic abscess 6 weeks after a WT strain was isolated from the same patient. The impact on the fitness was also assessed. METHODS: The genomes of both S. marcescens isolates were sequenced using Illumina technology, assembled, annotated and compared with each other. PCR amplification followed by Sanger sequencing was carried out to confirm the mutation. Complementation of the resistant isolate with a recombinant plasmid harbouring the WT gene was performed. The growth rates were measured for both isolates in LB medium. RESULTS: Comparative genomic analysis disclosed only one frameshift mutation (690delG) in the cpxA gene, which codes for the histidine kinase of a two-component system (TCS). This change introduced a premature termination codon, leading to the truncated CpxA_HatR variant that contained 234 amino acids instead of 464. Complementation, which consisted of transfer of the WT cpxA into the resistant S. marcescens derivative, restored completely its susceptibility to ESCs, aminoglycosides and ciprofloxacin, thus confirming the contribution of the CpxA_HatR variant to resistance. Growth analysis showed that the fitness of the resistant isolate was unchanged. CONCLUSIONS: This study shows for the first time that constitutive activation of the Cpx pathway can per se confer resistance to ESCs and ciprofloxacin, in addition to the aminoglycoside resistance usually described. It sheds new light on the role of altered TCSs in fostering bacterial survival.

Endogenous endophthalmitis: New insights from a 12-year cohort study.

OBJECTIVES: To describe the clinical and microbiological characteristics of patients with endogenous endophthalmitis (EE), determine factors associated with outcome and propose a management plan for EE. METHODS: Retrospective case series in two tertiary referral centers from 2010 to 2022. RESULTS: Sixty-four eyes of 53 patients were included. Bilateral involvement occurred for 11/53 patients (21%). Ocular symptoms were the only first manifestation of the disease in 36/53 (68%) of cases; signs of sepsis were evident in 17/53 (32%). Imaging tests detected at least one extraocular focus of infection in 34/53 patients (64%), with contrast-enhanced thoraco-abdominopelvic computed tomography showing relevant findings in 28/50 (56%) of cases. EE was microbiologically confirmed in 43/53 patients (81%); the organisms involved were: Gram-positive bacteria (19/53, 36%), Gram-negative bacteria (13/53, 25%) and Candida sp. (11/53, 21%). Klebsiella pneumoniae was the most common bacteria (10/32, 31%). Blood cultures were positive in 28/53 patients (53%) and eye samples in 11/41 eyes (27%). All patients were treated with systemic antimicrobial therapy, 39/64 eyes (61%) received anti-infective intravitreal injection(s) and 17/64 eyes (27%) underwent vitrectomy. Four patients (8%) died due to uncontrolled systemic infection. Final visual acuity (VA) was < 20/400 in 28/57 eyes (49%) and ocular structural loss (bulbar phthisis or enucleation/evisceration) was reported in 18/64 eyes (28%). In multivariate analysis, initial VA was the only parameter associated with visual and/or structural loss of the eye (OR = 24.44 (4.33-228.09) and 5.44 (1.33-26.18) respectively). CONCLUSIONS: EE remains a severe infection with a poor ocular outcome. We propose a standard protocol to improve diagnosis and medical management.

Evaluating and Managing the Microbial Contamination of Eye Drops: A Two-Phase Hospital-Based Study.

The microbial contamination of eye drop tips and caps varies between 7.7% and 100%. In seeking patient protection and continuous improvement, the Pharmacy Department in the Sterile Ophthalmological and Oncological Preparations Unit at Cochin Hospital AP-HP, Paris, France, conducted a two-phase study to compare the antimicrobial efficiency and practical use of standard packaging and a marketed eye drop container incorporating a self-decontaminating antimicrobial green technology by Pylote SAS at the tip and cap sites. The first phase was conducted in situ to identify the microbial contaminants of eye drops used in the hospital and community settings. A total of 110 eye drops were included for testing. Staphylococcus species were the most prevalent bacteria. Candida parapsilosis was detected in only one residual content sample and, at the same time, on the cap and tip. The second phase was performed in vitro, according to JIS Z2801. Reductions above one log in Staphylococcus aureus and Pseudomonas aeruginosa counts were noted in Pylote SAS eye drop packaging after 24 h of contact. The practical tests showed satisfactory results. Pylote SAS antimicrobial mineral oxide technology exhibited promising effects that combined effectiveness, safety, and sustainability to protect the patient by preventing infections due to the contamination of eye drop containers.

Multicenter evaluation of rapid antimicrobial susceptibility testing by VITEK®2 directly from positive blood culture.

STUDY OBJECTIVE: To compare the antimicrobial susceptibility testing (AST) performance of positive blood cultures (PBC) VITEK®2 off-label use (D0) and traditional VITEK®2 workflow using isolated colonies after overnight (D1). METHODS: Patient samples with monomicrobial Gram-negative rod or Gram-positive cocci in clusters bacteremia were tested on D0 and compared to D1 AST results in 7 laboratories in France. RESULTS: Overall, categorical and essential agreement rates were 98.4% and 96.7%, respectively. Very major discrepancy and major discrepancy rates for Enterobacterales and Staphylococci satisfied the NF EN ISO 20776-2 (2007) criteria for sepsis-relevant drugs. Very major discrepancies were >3% for amoxicillin-clavulanate (4.9%, 6/122), piperacillin-tazobactam (7.5%, 4/53) and meropenem (33%,1/3) for Enterobacterales and gentamicin for Staphylococci (4.6%, 4/87). CONCLUSION: Direct AST from PBC broths by VITEK®2 for Enterobacterales and Staphylococci is reliable and fast and may positively influence antimicrobial stewardship.

Effectiveness of third-generation cephalosporins or piperacillin compared with cefepime or carbapenems for severe infections caused by wild-type AmpC ß-lactamase-producing Enterobacterales: A multi-centre retrospective propensity-weighted study.

BACKGROUND: The optimal treatment regimen for infections caused by wild-type AmpC ß-lactamase-producing Enterobacterales remains controversial. This study compared the outcomes of bloodstream infections (BSI) and pneumonia according to the type of definitive antibiotic therapy: third-generation cephalosporin (3GC), piperacillin ± tazobactam, cefepime or carbapenem. METHODS: All cases of BSI and pneumonia caused by wild-type AmpC ß-lactamase-producing Enterobacterales over 2 years in eight university hospitals were reviewed. Patients who received definitive therapy consisting of either a 3GC (3GC group), piperacillin ± tazobactam (piperacillin group), or cefepime or a carbapenem (reference group) were included in this study. The primary endpoint was 30-day all-cause mortality. The secondary endpoint was treatment failure due to infection by emerging AmpC-overproducing strains. Propensity-score-based models were used to balance confounding factors between groups. RESULTS: In total, 575 patients were included in this study: 302 (52%) with pneumonia and 273 (48%) with BSI. Half (n=271, 47%) received cefepime or a carbapenem as definitive therapy, 120 (21%) received a 3GC, and 184 (32%) received piperacillin ± tazobactam. Compared with the reference group, 30-day mortality was similar in the 3GC [adjusted hazard ratio (aHR) 0.86, 95% confidence interval (CI) 0.57-1.31)] and piperacillin (aHR 1.20, 95% CI 0.86-1.66) groups. The likelihood of treatment failure was higher in the 3GC (aHR 6.81, 95% CI 3.76-12.4) and piperacillin (aHR 3.13, 95% CI 1.69-5.80) groups. The results were similar when stratifying the analysis on pneumonia or BSI. CONCLUSION: Treatment of included BSI or pneumonia caused by wild-type AmpC ß-lactamase-producing Enterobacterales with 3GC or piperacillin ± tazobactam was not associated with higher mortality, but was associated with increased risk of AmpC overproduction leading to treatment failure compared with cefepime or a carbapenem.

Infectious complications in out-of-hospital cardiac arrest patients in the therapeutic hypothermia era.

OBJECTIVES: Infectious complications are frequently reported in critically ill patients, especially after cardiac arrest. Recent and widespread use of therapeutic hypothermia has raised concerns about increased septic complications, but no specific reappraisal has been performed. We investigated the infectious complications in cardiac arrest survivors and assessed their impact on morbidity and long-term outcome. DESIGN: Retrospective review of a prospectively acquired intensive care unit database. SETTING: A 24-bed medical intensive care unit in a French university hospital. PATIENTS: Between March 2004 and March 2008, consecutive patients admitted for management of resuscitated out-of-hospital cardiac arrest were considered. Patients dying within 24 hrs were excluded. All patients' files were reviewed to assess the development of infection. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of the 537 patients admitted after cardiac arrest, 421 were included and 281 patients (67%) presented 373 infectious complications. Pneumonia was the most frequent (318 episodes), followed by bloodstream infections (35 episodes) and catheter-related infections (11 episodes). When grouped together, Gram-negative bacteria were the most frequently isolated infectious germs (64%), but the main pathogen detected was Staphylococcus aureus (57 occurrences). Both application itself (83 vs. 73%; p = .02) and duration (1244 vs. 1176 mins; p = .05) of therapeutic hypothermia were significantly more frequent in infected patients. Infection was associated with increased mechanical ventilation duration (6 [2-9] vs. 3 [2-5.5] days; p < .001) and intensive care unit length of stay (7 [4-10] vs. 3 [2-7] days; p < .001). Nonetheless, there was no impact on intensive care unit mortality (174 [62%] vs. 92 [66%] patients; p = .45) or on favorable neurologic outcome (cerebral performance category 1-2, 102 [36%] vs. 47 [34%] patients; p = .58). CONCLUSIONS: Infectious complications are frequent after cardiac arrest and may be even more frequent after therapeutic hypothermia. Despite increase in care costs, long-term and clinically relevant outcomes do not seem to be impaired. This should not discourage the use of therapeutic hypothermia in cardiac arrest survivors.

Unusual "flesh-eating" strain of Escherichia coli.

We report an exceptional case of life-threatening Escherichia coli-induced necrotizing fasciitis. A combined host-pathogen genetic analysis explained the phenotype: the host displayed a susceptibility to intravascular coagulation, and the strain was capable of producing a necrotic toxin (cytotoxic necrotizing factor 1), showing how E. coli can be a dermonecrotic pathogen.

Proficiency program for real-time PCR diagnosis of Bordetella pertussis infections in French hospital laboratories and at the French National Reference Center for Whooping Cough and other Bordetelloses.

With the support of a ministerial program for innovative and expensive technologies, dedicated to the economic evaluation of laboratory diagnosis of pertussis by real-time PCR, external quality assessment for real-time IS481 PCR was carried out. Coordinated by the National Centre of Reference of Pertussis and other Bordetelloses (NCR), this study aimed to harmonize and to assess the performances of eight participating microbiology hospital laboratories throughout the French territory. Between January 2006 and February 2007, 10 proficiency panels were sent by the NCR (ascending proficiency program), representing a total of 49 samples and including eight panels to analyze and evaluate the global sensitivity and specificity of real-time PCR, one to assess the limit of detection, and one to evaluate nucleic acid extraction methods. As part of the descending proficiency program, extracted DNA from clinical samples was sent by the eight participating laboratories in different panels and analyzed by the NCR. In the ascending proficiency analysis, the sensitivity and specificity of the real-time PCR methods were 92.2% and 94.3%, respectively. The limit of detection of the different methods ranged between 0.1 and 1 fg/microl (0.2 to 2 CFU/microl). The nucleic acid extraction methods showed similar performances. During the descending proficiency analysis, performed with 126 samples, the result of the NCR for 15 samples (11.9%) was discordant with the result obtained by the source laboratory. Despite several initial differences, harmonization was easy and performances were homogeneous. However, the risk of false-positive results remains quite high, and we strongly recommend establishment of uniform quality control procedures performed regularly.

Neisseria gonorrhoeae antibiotic resistance in Paris, 2005 to 2007: implications for treatment guidelines.

Quinolone-resistant Neisseria gonorrhoeae rates have increased worldwide since 1994. The objective of this study was to appraise: (i) the antimicrobial susceptibility of Neisseria gonorrhoeae in a venereology clinic in Paris, between 2005 and 2007; and (ii) the factors associated with quinolone-resistant N. gonorrhoeae. A prospective study of consecutive cases was performed for the period 2005 to 2007. Susceptibility of N. gonorrhoeae to five antibiotics (ciprofloxacin, ceftriaxone, spectinomycin, penicillin G and tetracycline) was tested systematically. Clinical and epidemiological data were collected using a standardized form. Male-to-female sex ratio was 22.0. Median age was 30.0 years. Of 115 cases, 84 occurred in men having sex with men (72.6%) and 22 involved the anorectal area (19.1%). The rate of quinolone-resistant N. gonorrhoeae was 37.4% (43/115), without significant association with gender, age, sexual behaviour, past history of sexually transmitted diseases and susceptibility to other antibiotics. All N. gonorrhoeae were susceptible to ceftriaxone and spectinomycin. The rate of quinolone-resistant N. gonorrhoeae in Paris has been increasing since 2004. Ceftriaxone remains the gold standard treatment.

Invasive group B streptococcal infections in infants, France.

Clinical features and molecular characterization of 109 group B streptococci causing neonatal invasive infections were determined over an 18-month period in France. Sixty-four percent of the strains were from late-onset infections, and 75% were capsular type III. The hypervirulent clone ST-17 was recovered in 80% of meningitis cases.

Performance of chromID ESBL, a chromogenic medium for detection of Enterobacteriaceae producing extended-spectrum beta-lactamases.

The chromogenic agar medium chromID ESBL (bioMérieux) was compared with BLSE agar medium (AES) for selective isolation and presumptive identification of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae from clinical samples. A total of 765 samples (468 rectal swabs, 255 urine samples and 42 pulmonary aspirations) obtained from 547 patients was processed. All bacterial strains isolated on either medium were further characterized using biochemical tests, and ESBL producers were confirmed by synergy testing. Genetic characterization of ESBL genes was determined by PCR. A total of 33 ESBL-producing Enterobacteriaceae strains [Escherichia coli (n=16), Klebsiella pneumoniae (n=8), Enterobacter spp. (n=3), Citrobacter spp. (n=5) and Proteus mirabilis (n=1)] was recovered. The sensitivity after 24 h incubation was 88 % for chromID ESBL and 85 % for BLSE agar. At 48 h, the sensitivity of chromID ESBL increased to 94 % and was higher than that obtained with BLSE agar. The positive predictive value at 24 h for chromID ESBL was 38.7 % [95 % confidence interval (95 % CI) 28.3 -50.2 %)], which was significantly higher than that for BLSE agar [15.4 %, 95 % CI 10.1 -21.5 %]. On both media, false-positive results were mostly due to Pseudomonas aeruginosa and to Enterobacteriaceae overproducing chromosomal cephalosporinase (Enterobacter spp.) or a chromosomal penicillinase (Klebsiella oxytoca). This study showed that chromID ESBL, a ready-to-use chromogenic selective medium, is sensitive and specific for rapid, presumptive identification of ESBL-producing Enterobacteriaceae. Its chromogenic properties and its selectivity are particularly useful in specimens containing resident associated flora.

Comparative evaluation of Strepto B ID chromogenic medium and Granada media for the detection of Group B streptococcus from vaginal samples of pregnant women.

Two types of selective media, the chromogenic medium Strepto B ID and two non-chromogenic media Strepto B agar and the Granada medium, were tested and compared to blood agar plates (BAP) for screening of Group B streptococcus vaginal colonization in pregnant women. All tested media were comparable in terms of sensitivity however, their use in routine laboratories may markedly facilitate the rapid detection of GBS in vaginal samples.

Pertussis and respiratory syncytial virus infections.

During the winter 2005-2006, all infants <4 months of age admitted for bronchiolitis or acute respiratory tract infection in a tertiary care pediatric hospital in Paris were tested for respiratory syncytial virus (RSV) and pertussis with real-time polymerase-chain reaction (RT-PCR). A positive pertussis-PCR was found in 14/90 (16%) infants infected with RSV and in 5/30 negative for RSV. Similar clinical symptoms were found in all RSV-positive infants with or without pertussis co-infection. Most infants (73%) were not vaccinated against pertussis, and the other children had received one or two injections. In conclusion, pertussis-RSV co-infection is common in young infants, and pertussis-PCR should be used, whenever available.

Impact of Sequential Culture Results on Diagnosis and De-Escalation of the Antibiotic Regimen in Joint and Bone Infections.

BACKGROUND: According to existing guidelines, orthopedic specimens collected in joint and bone infections (JBI) in our institution are cultured on several media sets and incubated for two, seven, and 14 days. The optimal timing for de-escalation of the first-line antibiotic combination according to the culture results needs to be defined. METHODS: Single-center, retrospective analysis of all adult patients with a first documented episode of JBI between May 2012 and April 2013. RESULTS: Ninety patients were included, 51 males (57%), median age 58 y (range 18-87 y), with prosthesis infection in 62 cases (69%). Rapidly growing pathogens (Staphylococcus aureus [n = 36] and Enterobacteriaceae [n = 12]) usually were diagnosed within two days, whereas coagulase-negative staphylococci (n = 25) and Propionibacterium acnes (n = 13) generally were identified after seven days (p < 10-5). Positive culture results at day 2 fit with definitive microbiological diagnosis in 95% of cases, and prolonged incubation led to the identification of additional micro-organisms in only four of 76 patients (5%) with day-2-positive cultures. Conversely, for those with negative two-day culture (n = 14), the seven-day culture allowed identification of less virulent pathogens in eight cases (57%). CONCLUSIONS: Our results suggest that, in JBI, de-escalation of the empirical antibiotic regimen can be based on micro-organisms identified on the two-day culture set. The impact of such a strategy on clinical outcomes, antibiotic consumption, and costs needs to be assessed in larger studies.

Relation between presence of extended-spectrum ß-lactamase-producing Enterobacteriaceae in systematic rectal swabs and respiratory tract specimens in ICU patients.

BACKGROUND: The choice of empirical antimicrobial therapy for pneumonia in intensive care unit (ICU) is a challenge, since pneumonia is often related to multidrug-resistant pathogens, particularly extended-spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E). To prevent the overuse of broad-spectrum antimicrobial therapy, the main objective of this study was to test the performance of digestive colonization surveillance as a predictor of ESBL-E presence or absence in respiratory samples performed in ICU and to evaluate the impact of time sampling (≤5 days or >5 days) on such prediction. DESIGN: Multicentric retrospective observational study, including every patient with a respiratory tract specimen positive culture and a previous rectal ESBL-E screening performed within 7 days before the respiratory sample, between January 2012 and December 2014. Results were analyzed in two groups: respiratory samples obtained during the first 5 days of ICU stay (early group) and respiratory samples obtained after 5 days (late group). INTERVENTIONS: none. RESULTS: Among 2498 respiratory tract samples analyzed corresponding to 1503 patients, 1557 (62.3%) were performed early (≤5 days) and 941 (37.7%) later (>5 days). Positivity rates for ESBL-E were 15.0 and 36.8% for rectal swabs in the early and late groups, respectively. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values and likelihood ratios were calculated for ESBL-E digestive colonization as a predictor of ESBL-E presence in respiratory samples. PPVs of ESBL-E digestive colonization were 14.5% (95% CI [12.8; 16.3]) and 34.4% (95% CI [31.4; 37.4]), for the early and late groups, respectively, whereas NPVs were 99.2% (95% CI [98.7; 99.6]) and 93.4% (95% CI [91.9; 95.0]), respectively. CONCLUSIONS: Systematic surveillance of ESBL-E digestive colonization may be useful to limit the use of carbapenems when pneumonia is suspected in ICU. When rectal swabs are negative, the risk of having ESBL-E in respiratory samples is very low even after 5 days of ICU stay.

Rapid detection of the "highly virulent" group B Streptococcus ST-17 clone.

Group B streptococcus (GBS) is a leading cause of neonatal morbidity and mortality. Multilocus sequence typing (MLST) revealed that the sequence type ST-17 defines a "highly virulent" serotype III clone strongly associated with neonatal invasive infections. Our aim was to identify a target sequence enabling rapid, simple, and specific detection of this clone by a real-time PCR assay. Conventional methods for DNA manipulation and gene analyses were used to characterize the gbs2018 gene variant specific for ST-17 clone and to design ST-17- and GBS-specific primers. Conventional and real-time PCR assays were developed to detect GBS and ST-17 clones in bacterial cultures and directly on clinical samples. One hundred and fifty-six French GBS strains from various geographical areas in France isolated between 1990 and 2005 were screened by PCR with ST-17-specific primers. Forty strains were positive, and all were validated by MLST as ST-17. A representative sampling of 49 ST-17-PCR-negative strains was confirmed by MLST as non-ST-17. Real-time PCR was further used to directly test 85 vaginal samples. Among these, 13 were GBS-positive, and one was identified as ST-17. The association between strain invasiveness and ST-17 lineage in neonates with late onset disease was highly significant: 78% (P<0.0001) of strains isolated were ST-17. In conclusion, an ST-17-specific gbs2018 allele was identified and used to develop a sensitive and specific rapid-screening molecular assay for identifying ST-17 "highly virulent" GBS. Using this technique, accurate identification of women and neonates colonized by ST-17 can be readily achieved within less than 2 h.

Presepsin (sCD14-ST) secretion and kinetics by peripheral blood mononuclear cells and monocytic THP-1 cell line.

Presepsin could help for early diagnosis of systemic infection. Little is known regarding its kinetics. We studied presepsin concentration after challenge with bacterial agonist lipopolysaccharide (LPS) stimulation in peripheral mononuclear cells (PMNC) collected from 5 healthy volunteers and in a human cell line of monocytic cells (THP1). In PMNC, an exposure to LPS (100 ng/mL) induced an increase of median presepsin levels as early as hour 1 (+31%, p=0.007), concomitantly to IL-6 synthesis. In THP1 cells, presepsin was detected at 1 hour after LPS exposure, and peaked at 3 hours, in THP1 cells. In conclusion, we report here that presepsin, a surrogate marker of the host response to bacteria, increases early in PMNC and in a monocytic cell lineage. Our findings might confirm the potential usefulness of presepsin bedside as an early marker of infectious diseases.

Comparative evaluation of 5 different selective media for Group B Streptococcus screening in pregnant women.

We compared the performances and the cost-effectiveness of 5 selective media for Group B Streptococcus (GBS) screening in vaginal samples from pregnant women. The usefulness of these media is unquestionable for GBS screening; the choice will depend largely on the laboratory organization.

Association between Staphylococcus aureus alone or combined with Pseudomonas aeruginosa and the clinical condition of patients with cystic fibrosis.

BACKGROUND: The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in cystic fibrosis (CF) patients has increased and MRSA seems to be associated with a poorer prognosis. The aim of this study was to assess the prevalence and clinical consequences of MRSA and methicillin-susceptible Staphylococcus aureus (MSSA), associated or not associated with Pseudomonas aeruginosa (PA). METHODS: In a retrospective study on 419 sputum producer patients (293 adults and 126 children >7 years of age), we recorded patient characteristics, lung function, nutritional status, i.v. antibiotics and hospitalisations, the presence of SA and/or PA and FEV1 decline over 2 years. RESULTS: SA was found in 72% of the patients: MSSA in 68.2% of children and 48.8% of adults; MRSA in 17.5% of children and 17.8% of adults. Sixty percent of MRSA patients and 60.4% of MSSA patients also harboured PA. The rate of deterioration of clinical status of the various groups, as assessed from respiratory function, i.v. antibiotic courses and hospitalisations, increased in the order: no SA/no PA, MSSA alone, MRSA alone, MSSA/PA, MRSA/PA, and PA alone. Nutritional status did not differ between groups. Results were roughly similar for children and adults. The yearly FEV1 decline was significantly higher only for MRSA/PA patients (p=0.03) compared to no SA/no PA patients. CONCLUSION: Clinical condition of CF patients with MSSA only or MRSA only appeared similar, whereas MRSA/PA patients had more severe respiratory function than MSSA/PA patients. In CF patients, MRSA might be more deleterious than MSSA only when associated with PA.