Citrobacter Koseri Research Articles

Choc septique après transfusion d’un concentré plaquettaire contaminé par Citrobacter koseri chez une patiente en aplasie fébrile post-chimiothérapie

The bacterial transfusion risk is currently the greatest infectious risk of blood transfusion. We report the case of a child with postchemotherapy febrile neutropenia who presented septic shock following platelet transfusion contaminated with Citrobacter koseri. The life-threatening development could have been avoided by strict compliance with good clinical practice. The stability of mortality rates due to adverse effects of bacterial proliferation during platelet transfusions in France since 1994 calls for optimization of all preventive measures throughout the transfusion chain and perfect knowledge of transfusion rules by medical staff and care givers.

BlaNDM-1 Carriage on IncR Plasmid in Enterobacteriaceae Strains.

Four NDM-1-producing Enterobacteriaceae strains (three Klebsiella pneumoniae and one Citrobacter koseri) were isolated between 2009 and 2011 through a nationwide surveillance for carbapenem-resistant Enterobacteriaceae in Croatia to study the molecular genetic background of blaNDM and the responsible plasmid types. Phenotypically, the clinical strains proved to be multidrug resistant. All strains remained susceptible to tigecycline and colistin. The clinical strains harbored variable antibiotic resistance determinants, notably, blaNDM-1, blaTEM-1, blaSHV-1, blaSHV-12, blaOXA-1, blaOXA-9, blaCTX-M-15, blaCMY-4, qnrB1, and aac(6')Ib-cr in different combinations. Two K. pneumoniae belonged to sequence type ST15 and one strain to ST16. As for the plasmid types, C. koseri and one of the ST15 K. pneumoniae carried IncR, and the second ST15 K. pneumoniae carried IncR and colE. The K. pneumoniae ST16 strain hosted A/C and colE plasmids. The blaNDM-1 gene was detected on conjugative high-molecular-weight plasmids, namely, A/C and IncR types. It is noteworthy that this is the first description of K. pneumoniae ST16 expressing NDM-1 in Europe. Remarkably, our study underscores the importance of the IncR plasmid as a reservoir of multidrug resistance. To the best of our knowledge, the IncR plasmid carrying blaNDM-1 in C. koseri is reported for the first time.

Three-step biocatalytic reaction using whole cells for efficient production of tyramine from keratin acid hydrolysis wastewater.

Tyramine has been paid more attention in recent years as a significant metabolite of tyrosine and catecholamine drug and an intermediate of medicinal material and some drugs. In this study, an effective, green, and three-step biocatalytic synthesis method for production of tyramine starting from serine in keratin acid hydrolysis wastewater was developed and investigated. Serine deaminase from Escherichia coli was first combined with tyrosine phenol-lyase from Citrobacter koseri, to convert L-serine to L-tyrosine. L-Tyrosine can then be decarboxylated to tyramine by tyrosinede carboxylase from Lactobacillus brevis. All these enzymes originated from recombinant whole cells. Serine deaminaseand tyrosine phenol-lyase could efficiently convert L-serine in wastewater to L-tyrosine at pH 8.0, 37 °C, and Triton X-100 of 0.04% when tyrosine phenol-lyase and its corresponding substrates were sequentially added. Tyrosine conversion rate reached 98 % by L-tyrosine decarboxylase. In scale-up study, the conversion yield of L-serine in wastewater to tyrosine was up to 89 %. L-Tyrosine was decarboxylated to tyramine with a high yield 94 %. Tyramine hydrochloride was obtained with a total yield 84 %. This study has provided an efficient way of recycling keratin acid hydrolysis wastewater to produce tyramine.

The pla gene, encoding plasminogen activator, is not specific to Yersinia pestis

Here we present evidence to show that the pla gene, previously thought to be specific to Yersinia pestis, occurs in some strains of Citrobacter koseri and Escherichia coli. This means that detection of this gene on its own can no longer be taken as evidence of detection of Y. pestis.

Answer to October 2015 Photo Quiz

Answer: Streptococcus pyogenes. Figure 1 in the photo quiz demonstrates hypergranular, vacuolated neutrophils with intracellular cocci forming chains, resembling the genus Streptococcus. In light of the clinical features and blood film, a presumptive diagnosis of Streptococcus pyogenes toxic shock syndrome was made. Six hours following the blood film observation, growth of Gram-positive cocci in chains was detected in blood culture, which was subsequently confirmed to be S. pyogenes. As a result of the blood film findings, intravenous clindamycin was added; however, 19 h after presentation, the patient died of multiorgan failure. The published literature suggests that observation of bacteria on routine blood film is rare; case reports involving Capnocytophaga canimorsus (1), Citrobacter koseri (2), and Streptococcus pneumoniae (3) have been described, plus a case series of four neonates involving Staphylococcus aureus and coagulase-negative staphylococci (4). A larger case series, published in 1966, reported 26 bacteremic patients with bacteria observed within leukocytes on routine blood films (S. aureus, S. pneumoniae, Escherichia coli, Klebsiella pneumoniae, Neisseria meningitidis, Proteus species, viridans group Streptococcus, beta-hemolytic Streptococcus, and “paracolon bacillus”) (5). To the best of our knowledge, this is the first case of S. pyogenes observed in a routine blood film. The high fatality rate among these published cases (24 of 33 patients died) (1,–5) likely reflects the poor diagnostic sensitivity of blood films except in patients with very high bacterial loads observed during overwhelming septicemia, such as in our case. The use of buffy-coat smears may improve sensitivity (to a limit of detection of 104 CFU/ml) but is labor- and time-consuming, prohibiting its routine use (6). Bacteria observed during routine blood film examination should be discussed immediately with the treating physician, as the result may be used to predict a microbiological diagnosis and assist with choice of empirical antimicrobial and adjunctive therapy and portends a poor patient outcome. (See page 3109 in this issue [doi:10.1128/JCM.02824-13] for photo quiz case presentation.)

Multiwavelength Resonance Raman Characterization of the Effect of Growth Phase and Culture Medium on Bacteria.

We examine the use of multiwavelength ultraviolet (UV) resonance-Raman signatures to identify the effects of growth phase and growth medium on gram-positive and gram-negative bacteria. Escherichia coli (E. coli), Citrobacter koseri (C. koseri), Citrobacter braakii (C. braakii), and Bacillus cereus (B. cereus) were grown to logarithmic and stationary phases in nutrient broth and brain heart infusion broth. Resonance Raman spectra of bacteria were obtained at multiple wavelengths between 220 and 260 nm; a range that encompasses the resonance frequencies of cellular constituents. We find that spectra of the same bacterial species exhibit differences due to both growth condition and growth phase, but the larger differences reflect changes due to growth phase. The differences in the Raman spectra correlate with genetic differences among the species. Using a Pearson correlation based algorithm, we achieve successful identification of these bacteria in 83% of the cases.

Low-level antimicrobial resistance of Enterobacteriaceae isolated from the nares of pig-exposed persons.

Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) have recently emerged in livestock and humans. Therefore, this study assessed the carriage of Enterobacteriaceae in the anterior nares and associated antimicrobial resistance in pig-exposed persons. Nasal swabs were enriched in non-selective broth and then plated on MacConkey and ESBL-selective agars. Species was confirmed by matrix-assisted laser-desorption ionization-time-of-flight mass spectrometry (MALDI-ToF MS). Antimicrobial susceptibility testing was performed according to European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. Of 114 pig-exposed persons tested, Enterobacteriaceae were detected in the nares of 76 (66·7%) participants. The predominant species were Proteus mirabilis (n = 17, 14·9%), Pantoea agglomerans (n = 13, 11·4%), Morganella morganii (n = 9, 7·9%), Citrobacter koseri (n = 9, 7·9%), Klebsiella pneumoniae, Escherichia coli and Proteus vulgaris (each n = 8, 7·0%). ESBL-E were not detected. Of all isolates tested, 3·4% were resistant against ciprofloxacin, 2·3% against gentamicin, 23·9% against trimethoprim-sulfamethoxazole and 44·3% against tigecycline. Despite the high prevalence of ESBL-E in livestock, pig-exposed persons did not carry ESBL-E in their nares. This finding is important, because colonization of the nasal reservoir might cause endogenous infections or facilitate transmission of ESBL-E in the general population.

English

BACKGROUND & OBJECTIVES: Citrobacter species have emerged as important nosocomial pathogens. The infections caused by this organism include UTI, wound infection, Neonatal sepsis, pulmonary infection, brain abscess, meningitis. The organism is recovered from a variety of clinical specimen including pus, urine, sputum. Antibiotic resistance is on rise among the Citrobacter spp. The present study was taken up to study the infections and antibiotic susceptibility pattern of Citrobacter spp. in our setup. MATERIALS AND METHODS: The study included 40 isolates of Citrobacter spp. isolated from a variety of clinical samples. Citrobacter spp. isolated were speciated using biochemical reactions. The antibiotic sensitivity testing was done by Modified Kirby-Bauer method. The risk factors associated were noted from the case records. RESULTS: Of the 40 isolates of Citrobacter species, 8 were identified as Citrobacter freundii, 18 as Citrobacter koseri, 14 as other species of Citrobacter. Of the 40 isolates, 25 were monomicrobial and the other 15 were polymicrobial. Majority of the Citrobacter isolates were from pus and Diabetes mellitus was the important risk factor. CONCLUSION: The infections are usually nosocomially acquired and are more commonly seen in patients with underlying risk factors. The incidence of these infections in hospital could be reduced by strict adherence to infection control practices and antibiotic policy.

Novel antibiotic combination approved for complicated infections

Novel antibiotic combination approved for complicated infections

Isolation and characterization of potential probiotic bacteria from pustulose ark (Anadara tuberculosa) suitable for shrimp farming

In aquaculture, probiotics have been tested for enhancing the immune system and promoting growth and survival rate of many marine species like shrimp and mollusks. In order to isolate bacteria with a high probiotic potential for marine shellfish aquaculture, homogenates of the gastrointestinal tract from adult mangrove cockle, Anadara tuberculosa , were obtained to perform in vitro and in vivo assays. Isolates were tested in vitro for hemolytic activity, hydrophobicity, tolerance to ammonia nitrogen, salinity and pH as well as for growth kinetics, extracellular enzymatic activity, autoaggregation, coaggregation and molecular identification. Three bacteria with high degree of hydrophobicity (>60% adherence to p-xylene) and four bacteria with medium hydrophobicity, which showed different patterns of attachment to monopolar solvents (chloroform and ethyl acetate) and a high tolerance to ammonia nitrogen (200 mg L -1 ), were selected. Six different treatments: T1 (without addition of cultured bacteria); T2 (MAt29, Enterococcus casseliflavus ); T3 (MAt35, Citrobacter koseri ); T4 (GAtB1, Bacillus subtilis subtilis ); T5 (GAt7, Staphylococcus sp.); and T6 (1:1:1:1 mix of strains T2, T3, T4 and T5), were used to evaluate the specific growth rate, and cellular immune response of the shrimp Litopenaeus vannamei . The best specific growth rate was observed for T6 and T4 treatments related to Bacillus subtilis subtilis . A significant difference in total hemocytes count ( P < 0.05) was found for T4 treatment with respect to control group. Strains isolated from A. tuberculosa had a beneficial effect on the growth and immune response of L. vannamei , so they have potential use as probiotics in aquaculture of marine shellfish.

Optimization of profenofos degradation by a novel bacterial consortium PBAC using response surface methodology

Profenofos (PFF), an organophosphate (OP) insecticide, has been widely used for last two decades to control insect pests. Extensive use of this toxic pesticide is leading to serious environmental consequences which impose development of methods to reduce the environmental burden of PFF using an environmental friendly and cost effective approach. In this study, a PFF degrading bacterial consortium PBAC consisting of Achromobacter xylosoxidans, Pseudomonas aeruginosa, Bacillus sp. and Citrobacter koseri, was developed. Interestingly, compared to pure isolates, the consortium degraded PFF more efficiently. Following a 23 full factorial central composite design based on Response Surface Methodology (RSM), different culture conditions were optimized for PFF degradation. The optimal pH, temperature and inoculum size were found to be 6.83, 34.59 °C (∼35 °C) and 0.59 g L−1 respectively to achieve maximal degradation of PFF (93.39%). Analysis of the degradation products revealed that 4-bromo-2-chlorophenol (BCP) was the major metabolite of PFF which was further metabolized to simpler products. Importantly, PBAC was capable of degrading a wide range of OP and other pesticides which renders it a useful tool for remediation of soil with a cocktail of contaminants.

In vitro spectrum of pexiganan activity when tested against pathogens from diabetic foot infections and with selected resistance mechanisms.

Pexiganan, a 22-amino-acid synthetic cationic peptide, is currently in phase 3 clinical trials as a topical antimicrobial agent for the treatment of mild infections associated with diabetic foot ulcers. Bacterial isolates from the 2013 SENTRY Antimicrobial Surveillance Program designated as pathogens from diabetic foot infections (DFI) and Gram-negative and -positive pathogens from various infection types that harbored selected resistance mechanisms/phenotypes were tested against pexiganan in reference cation-adjusted Mueller-Hinton broth. The MIC50 and MIC90 against all organisms tested from DFI were 16 and 32 μg/ml, respectively. Escherichia coli, Klebsiella pneumoniae, Citrobacter koseri, Enterobacter cloacae, Acinetobacter species, and Pseudomonas aeruginosa MIC values ranged from 8 to 16 μg/ml. Pexiganan MIC values among Staphylococcus aureus (methicillin-resistant S. aureus [MRSA] and methicillin-susceptible S. aureus [MSSA]), beta-hemolytic streptococci, and Enterococcus faecium ranged from 8 to 32 μg/ml. Pexiganan activity was not adversely affected for members of the family Enterobacteriaceae or P. aeruginosa that produced β-lactamases or resistance mechanisms to other commonly used antimicrobial agents. Decreased susceptibility to vancomycin did not affect pexiganan activity against S. aureus or E. faecium. Enterococcus faecalis appears to be intrinsically less susceptible to pexiganan (MIC, 32 to 256 μg/ml). The "all organism" MIC90 of 32 μg/ml for pexiganan in this study was >250-fold below the pexiganan concentration in the cream/delivery vehicle being developed for topical use.

Breast implant infection after radical mastectomy with Citrobacter koseri: Case report

In this paper we are presenting the case report on a patient with breast implant infection after radical mastectomy caused by Citrobacter koseri. Breast implant infection recoverd after systemic antimicrobial therapy and implant removal. We reviewed the literature about breast implant infection and did not find case of Citrobacter koseri infection.

Citrobacter koseri Septicaemia in a Holstein Calf

A 4-day-old male Holstein calf with dull mentation, nystagmus and blindness was humanely destroyed and subject to necropsy examination. Gross lesions included severe suppurative meningitis characterized by diffuse cloudy thickening of the meninges, bilateral hypopyon and fibrinosuppurative polyarthritis affecting the hocks. Citrobacter koseri was isolated from the meninges, ocular fluid, synovial fluid, spleen and small intestine. Microscopically, there was neutrophilic and histiocytic meningitis with intralesional bacilli, endophthalmitis, neutrophilic splenitis and multiple renal microabscesses. Failure of passive transfer of colostrum was confirmed. This appears to be the first characterization of septicaemia in a calf caused by C. koseri, with lesions comparable with those described in human neonates.

Supporting the ceftaroline fosamil/avibactam Enterobacteriaceae breakpoint determination using humanised in vivo exposures in a thigh model

Previous in vivo studies using a human-simulated regimen of ceftaroline/avibactam 600/600mg every 8h (q8h) showed activity against extended-spectrum β-lactamase-, AmpC- and KPC-producing Enterobacteriaceae with minimum inhibitory concentrations (MICs) ≤1μg/mL. Here we sought to determine the efficacy of this human-simulated regimen against organisms with MICs ≥1μg/mL to help determine a breakpoint value that would reliability predict efficacy in humans. In total, 31 isolates (1 Escherichia coli, 9 Klebsiella pneumoniae, 9 Enterobacter cloacae, 1 Citrobacter koseri, 2 Serratia marcescens, 1 Klebsiella oxytoca and 8 Pseudomonas aeruginosa) with ceftaroline/avibactam MICs of 1 to 16μg/mL were tested in a murine immunocompromised thigh infection model; 15 isolates were also tested in an immunocompetent model. Doses were given to simulate human free drug exposures of ceftaroline fosamil/avibactam 600/600mg q8h over 24h as a 1-h infusion by targeting the fT>MIC profile. Efficacy was evaluated as the change in log10 CFU compared with 0-h controls after 24h. Reductions in bacterial CFU in the neutropenic model were seen against a majority of isolates tested with MICs ≤4μg/mL, where fT>MIC was >55%. More variable efficacy was seen in isolates with MICs ≥8μg/mL, where fT>MIC drops below 40%. Overall activity was enhanced in the immunocompetent model. The humanised regimen of ceftaroline fosamil/avibactam 600/600mg q8h as a 1-h infusion showed predictable efficacy against isolates with various genotypic and phenotypic profiles and MICs ≤4μg/mL. These data provide valuable information to help determine a ceftaroline/avibactam breakpoint for Enterobacteriaceae.

Citrobacter koseri native valve endocarditis: A case report and review of the literature

We report a case of a 43-year-old man, with history of intravenous drug abuse and hepatitis C, admitted for infective tricuspid and aortic valve endocarditis due to Citrobacter koseri (C. koseri). C. koseri is a motile gram-negative bacillus that usually causes various infections in humans involving the urinary, gastrointestinal, and respiratory tracts. Infections are commonly reported in neonates, the elderly, and immunocompromised or debilitated hosts. It rarely causes infection in immunocompetent patients.

English

Respiratory tract infections (RTIs) are the most frequently-oc&shy;curring infections of all human diseases and have been frequently documented. This study investigated the antimicrobial resistance patterns among Gram negative respiratory tract isolates. A total of 309 non replicate Gram negative respiratory tract isolates were collected and identified. Molecular mechanisms of antimicrobial resistance pattern were characterized by phonotypic and genotypic methods including polymerase chain reaction (PCR) amplification and DNA sequencing of isolated genes. Gram negative isolates were Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Stenotrophomonas maltophilia, Escherichia coli, Enterobacter cloacae, Serratia rubidaea, Haemophilus influenza, Citrobacter koseri, Moraxella catarrhalis, Proteus mirabilis and Salmonella typhimurium with the following frequencies respectively (34.6, 26.6, 13.9, 7.7, 6.4, 5.5, 1.4, 1.3, 1, 1, 0.3 and 0.3%). S. maltophilia isolates were the highest that produced extended spectrum beta lactamase (ES&beta;L) with percentage of 75% and metallo beta lactamase (M&beta;L) with percentage of 71%, while P. aeruginosa isolates were the highest that produced class C beta lactamase (AmpC) with percentage of 86% and efflux pump with percentage of 73%. This study revealed two common mechanisms of antimicrobial resistance patterns, &beta;-lactamases production and efflux pump, among Gram negative respiratory tract pathogens up to molecular level. Key words: Resistance pattern, antimicrobial agents, respiratory, pathogens.

Intraoperative Vancomycin Use in Spinal Surgery

Retrospective case series. To demonstrate the microbial trends of spinal surgical site infections in patients who had previously received crystallized vancomycin in the operative bed. Prior large, case control series demonstrate the significant decrease in surgical site infection with the administration of vancomycin in the wound bed. A single institution, electronic database search was conducted for all patients who underwent spinal surgery who had received prophylactic crystalline vancomycin powder in the wound bed. Patients with a prior history of wound infection, intrathecal pumps, or spinal stimulators were excluded. A total of 981 consecutive patients (494 males, 487 females; mean age, 59.4 yr; range, 16-95 yr) were identified from January 2011 to June 2013. The average dose of vancomycin powder was 1.13 g (range, 1-6 g). Sixty-six patients (6.71%) were diagnosed with a surgical site infection, of which 51 patients had positive wound cultures (5.2%). Of the 51 positive cultures, the most common organism was Staphylococcus aureus. The average dose of vancomycin was 1.3 g in the 38 cases where a gram-positive organism was cultured. A number of gram-negative infections were encountered such as Serratia marcescens, Enterobacter aerogenes, Bacteroides fragilis, Enterobacter cloacae, Citrobacter koseri, and Pseudomonas aeruginosa. The average dose of vancomycin was 1.2 g in 23 cases where a gram-negative infection was cultured. Fifteen of the 51 positive cultures (29.4%) were polymicrobial. Eight (53%) of these 15 polymicrobial cultures contained 3 or more distinct organisms. Prophylactic intraoperative vancomycin use in the wound bed in spinal surgery may increase the incidence of gram-negative or polymicrobial spinal infections. The use of intraoperative vancomycin may correlate with postoperative seromas, due to the high incidence of nonpositive cultures. Large, randomized, prospective trials are needed to demonstrate causation and dose-response relationship.

Observations on Citrobacter species from a tertiary care health center with special reference to multi-drug resistance and presence of CTX-M gene.

Citrobacter is an important nosocomial pathogen and its multi-drug resistant (MDR) isolates are increasingly being reported across the globe. They are known to produce extended spectrum beta lactamase (ESBL) and harbor CTX-M gene. The aim was to isolate Citrobacter sp. from clinical specimens, analyze their MDR status and look for the presence of CTX-M gene. In this prospective study, Citrobacter isolates positive for ESBL on screening, were confirmed by combined disc method along with minimum inhibitory concentration (MIC) for cefotaxime. In selected cefotaxime resistant isolates, multiplex polymerase chain reaction was done for blaCTX-M gene. Of 146 Citrobacter sp. isolated, most (73%) were from admitted patients and hospital stay of >72 h and prior antibiotic intake were the most common associated factors. Maximum isolates were from pus (41.1%). Citrobacter freundii was the commonest species (49%) followed by Citrobacter koseri (28%); 79 were ESBL producers. Seventy were cefotaxime resistant as shown by MIC. blaCTX-M gene was detected in 15/40 of these isolates, all belonged to CTX-M group 1. Overall incidence of Citrobacter in our setup is low, but they were mostly MDR, and ESBL production was high, which is a cause of concern. blaCTX-M gene detection is important because of its rapid transmission to other bacterial species.

Medical and neurosurgical management of Citrobacter koseri, a rare cause of neonatal meningitis

Medical and neurosurgical management of Citrobacter koseri, a rare cause of neonatal meningitis