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Sai Vikram Alampoondi Venkataramanan, Lovin George, Kamal Kant Sahu, George M Abraham Department of Medicine, Saint Vincent Hospital, Worcester, MA, 01608, USACorrespondence: Kamal Kant SahuDepartment of Medicine, Saint Vincent Hospital, Worcester, MA, 01608, USAEmail drkksahu85@gmail.comIntroduction: Raoultella planticola is an aerobic gram-negative rod predominantly found in soil and aquatic environments. The typical reservoirs of Raoultella spp. include the gastrointestinal tract and the upper respiratory tract. It usually causes pneumonia, biliary tract infections, and bacteremia. Urinary tract infection (UTI) secondary to R. planticola is an uncommon entity. Less than 10 cases of R. planticola-associated UTIs in adults have been published in the literature to date.Objective: This is a single institution retrospective study undertaken to identify the epidemiology, patient characteristics, clinical spectrum, predisposing risk factors and the outcome of patients with UTI caused by R. planticola.Results: A total of 37 R. planticola isolates were identified in urine samples over a 5-year study period. The mean age of the patient population was 77 years. The most common comorbidity was diabetes mellitus, which was present in 16 patients. Only 3 patients had a history of steroid use, an immunosuppressive condition, or were on chemotherapy. The most common presenting complaint was altered mental status followed by fever. Resistance to ampicillin was found in 35 isolates which seems to be an intrinsic characteristic of Raoultella spp. and 2 isolates were multidrug-resistant, but still susceptible to ciprofloxacin. The average length of stay was 3 days, and the average duration of antibiotic administration was 8 days. Ciprofloxacin was the most frequently prescribed antibiotic (9 patients). The severity of infection ranged from simple cystitis in 15 patients to urosepsis in 2 patients and septic shock in 2 patients. There were no mortalities in our cohort.Conclusion: Our study revealed that patients with R. planticola UTI had higher proportion of diabetes mellitus, renal failure compared to the general population. Our study also confirms the intrinsic resistance to ampicillin of Raoultella spp., which has been documented previously in the literature.Keywords: infection, antibiotics, Raoultella, urinary tract infection, bacteriuria

Colistin (CST) is considered the last resort for the treatment of infectious diseases due to multidrug-resistant bacteria. Since the mcr-1 gene has been reported in Enterobacteriaceae isolated from food, animals, and humans in China, the prevalence of CST-resistant bacteria has been of great concern. Here, we investigated the prevalence of CST resistance and plasmid-mediated colistin-resistance genes (mcr) in gram-negative bacteria isolated among retail meats in Japan. CST-resistant bacteria were isolated from 310 domestic retail meats (103 chicken meat, 103 pork, and 104 beef) purchased between May 2017 and July 2018 from retail shops in Japan using CST-containing media and antimicrobial susceptibility testing. The mcr gene was investigated in isolates with a CST minimum inhibitory concentration of ≥1 μg/mL. Excluding the intrinsically CST-resistant isolates, CST-resistant bacteria were isolated from 39 of the total chicken meats (37.9%), 19 of the pork samples (18.4%), and 18 of the beef samples (17.3%). A total of 459 isolates were identified, out of which 99 were CST-resistant. CST resistance (resistance breakpoints: Aeromonas, >4 μg/mL; others, >2 μg/mL) was found in Aeromonas spp. (48/206, 23.3%), Yersinia spp. (5/112, 4.5%), Escherichia coli (23/39, 59%), Citrobacter spp. (4/26, 15.4%), Klebsiella spp. (2/23, 8.7%), Raoultella spp. (2/16, 12.5%), Enterobacter spp. (7/14, 50%), Pseudomonas spp. (1/8, 12.5%), Pantoea spp. (5/7, 71.4%), Ewingella spp. (1/4, 25%), and Kluyvera spp. (1/2, 50%). The mcr gene was detected in 16 isolates: mcr-1 in 14 isolates of E. coli from 10 chicken samples (9.7%), and mcr-3 in two isolates of Aeromonas sobria from pork and chicken samples (each 1.0%). The findings of this study highlight the necessity of surveillance of CST resistance and resistance genes in bacteria that contaminate retail meats.

Background Local data from the Asella Teaching and Referral Hospital in the town of Asella, Ethiopia reveal a high prevalence of extended-spectrum β-lactamase- (ESBL) producing Gram-negative bacteria (GNB) in clinical isolates. To investigate a possible route of transmission, we determined the proportions ESBL-producing GNB in isolates from flies caught in the hospital and in the town of Asella. Methods Flies were collected in August 2019 from the neonatal intensive care unit (NICU), the orthopedic ward, the hospital’s waste disposal area, and from a butchery situated 1.5 km from the hospital. After trapping, the flies were macerated and suspended in sterile normal saline. The suspensions were inoculated on MacConkey agar and incubated overnight. Species identification and antimicrobial susceptibility testing were performed using Vitek®-MS and VITEK® 2. Results In total, 103 bacterial isolates were obtained from 85 flies (NICU: 11 isolates from 20 flies, orthopedic ward: 10 isolates from 12 flies, waste disposal area: 37 isolates from 26 flies, butchery: 45 isolates from 27 flies). The proportions of ESBL-producing bacteria among isolates obtained from flies collected in the hospital compound were significantly higher (82%, 90%, and 57% in NICU, orthopedic ward and waste disposal area, respectively) compared to flies collected outside of the hospital compound (2% (@1/45) in the butchery) (p ≤ 0.001). The proportion of ESBL was 67% (6/9) among Raoultella spp. 67% (4/6) among Kluyvera spp., 56% (5/9) among Enterobacter spp., 50% (5/10) among E. coli, and 44% (8/18) among Klebsiella spp.. Of the 40 ESBL-genes detected, 85% were CTX-M-like, 83% TEM-like, 23% SHV-like, and 2% CTX-M-2-like. ESBL-producing bacteria showed higher rates of resistance against ciprofloxacin (66% vs. 5%), gentamicin (68% vs. 3%), piperacillin-tazobactam (78% vs. 5%), and trimethoprim-sulfamethoxazole (88% vs. 16%), compared to non-ESBL-producing bacteria. Conclusion A high proportion of ESBL was identified in isolates from flies caught in the hospital compound compared with isolates of flies collected at a distance of 1.5 km from the hospital. Flies can be potential vectors for transmission of multidrug-resistant (MDR) bacteria within hospitals. Further studies are needed to determine the source of MDR colonization in flies and possible impact of MDR for nosocomial infections.

Klebsiella spp. are important opportunistic pathogens commonly defined as environmental clinical mastitis agents. Despite Klebsiella mastitis being clinically impairing in cows and costly to the industry, only a few studies describe Klebsiella isolated from mastitis cases. The aim of this work was to characterize species of Klebsiella involved in clinical mastitis cases in Canada. Klebsiella isolated from clinical mastitis cases (n = 53) were identified to the species level using a biochemical test panel and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The rpoB gene sequence was used as the gold standard method and identified Klebsiella pneumoniae (n = 40), Klebsiella oxytoca (n = 9), Raoultella ornithinolytica (n = 2), and Raoultella planticola (n = 2). Raoultella, a genus closely related to Klebsiella, was also accurately identified using mass spectrometry but not via biochemical testing. Using the disc diffusion technique, 31 (58%) isolates were found to be susceptible to all antimicrobials tested (n = 18). The remaining 22 (42%) isolates were resistant to 1 or more of the following antimicrobials: kanamycin (2%), streptomycin (38%), spectinomycin (13%), sulfisoxazole (13%), and tetracycline (19%). The following antimicrobial resistance genes were identified: tetA, tetB, sul1, strA/strB, and aadA. Random amplified polymorphic DNA revealed the majority of our isolates as unrelated and having different patterns, indicating environmental contamination as the primary source of infection. All isolates were shown to be biofilm producers. In conclusion, although antimicrobial resistance was low for both Klebsiella and Raoultella species, genetically related Klebsiella spp. isolates appeared to be more resistant.

Introduction. Raoultella spp. representatives are Gram-negative rod-shaped bacteria of the Enterobacteriaceae family. These bacteria are commonly found in the natural environment. Aim. The aim of the study was to indicate the reliable method for Raoultella spp. strains identification, evaluate the susceptibility of Raoultella spp. strains to selected antimicrobials and to detect their resistance mechanisms to beta-lactams. Methodology. Susceptibility of the strains to chosen antimicrobials was determined using the automatic method. The presence of particular antimicrobial resistant mechanism and genes encoding ESBLs and MBLs was determined respectively with double-disc synergy test and commercially available kit – eazyplex SuperBug CRE test (Amplex Diagnostics) and standard PCR. For the selected strains, DNA sequencing was performed. Results. Amongst 105 of the examined Raoultella spp. strains, majority were sensitive to: imipenem (99.0 %), meropenem (98.1 %), gentamicin (93.3 %) and ciprofloxacin (92.4 %). Of the tested Raoultella strains, thirteen (12.4 %) produced ESBLs and one strain simultaneously ESBLs and MBLs. The DNA sequencing results were as follows: for all the reference strains the correct species identification was achieved, for the analysed strains two were identified as R. planticola and one as R. ornithinolytica . Conclusion. Although Raoultella spp. strains remain sensitive to antibiotics, there is a constant need to monitor the sensitivity of these bacteria to selected antimicrobials. Isolation of a multi-drug resistant R. ornithinolytica strain indicates that even the less frequently isolated species of Enterobacteriaceae family should be precisely identified because they might be of clinical importance and the particular strain can also produce enzymes that pose the greatest threat today.

The spread of antibiotic resistant organisms and those producing extended spectrum -lactamases (ESBL) has become a health care problem worldwide in communities and hospitals, as it leads to more complicated infections, longer duration of treatment, and increases in patient mortality. In the present study, we analyzed 226 clinical samples in order to assess the spread of ESBL-producing Enterobacteriaceae. 196 Enterobacteriaceae were identified and classified as members of the genera Pantoea, Klebsiella, Escherichia, Enterobacter, Serratia, Proteus, Citrobacter, and Raoultella. The results of susceptibility testing of isolated strains to 19 antibiotics showed that the most part of the isolates were highly resistant (p.0.01) to the tested -lactams: penicillins and penicillin like antibiotics (amoxicillin, ticarcillin and amoxicillin-clavulanic acid), first-generation cephalosporins (cephalexin), and second generation cephalosporins (cefoxitin). 60.20% of the Enterobacteriaceae isolates were multi-drug resistant (MDR) strains. Resistant isolates to third generation cephalosporins were tested for ESBL by tree methods, concluding its presence in 29.59% of the isolates by double-disk synergy test, 27.55% by the disk approximation method and by 31.63% double-disk test. High levels of MDR strains and ESBL- producing Enterobacteriaceae in our study suggest the need for applying specific infection control measures, and rational antibiotic use to reduce the selection pressure and prevent dissemination of resistant bacteria.

A 20 year-old female at 27-week gestation was admitted for threatened preterm delivery. Following an initially unremarkable hospital course for 12 days, the patient developed fever, chills, generalized malaise, abdominal pain, and diffuse myalgias on day 13 of hospitalization. Raoultella species was isolated from blood cultures on day 16 of hospitalization. The patient’s condition improved within 24 hours of symptom onset, prior to antibiotic initiation, and a premature, viable male infant at 29 weeks and 6 days of gestation was delivered via caesarean section four days later due to breech presentation in the setting of preterm labor. Here, we present the first case of a Raoultella species infection in a gravid female reported in the literature.

Urban wastewater treatment plants (UWTPs) are considered hot spots for the accumulation and transfer of antibiotic resistant bacteria and their genes. We investigated the prevalence, diversity, and genomic localization of β-lactamase resistance genes in wastewater from different parts of an UWTP, such as raw wastewater, wastewater from biological reactor, and treated wastewater, collected from the UWTP of Warsaw, Poland. In this study, we focused on gram-negative rods, mainly Enterobacteriaceae, and used Multiplex PCR to identify various β-lactamase resistance genes (bla). Susceptibility to a number of antibiotics and genomic localization of β-lactamase resistance genes were then determined using disc-diffusion and Southern hybridization methods, respectively. No differences in the frequency of different types of bla genes between the sampling points were discerned. Three new variants of β-lactamase genes (blaCMY-157, blaMOX-13, and blaFOX-15) were identified. Four bla genes (blaTEM-12, blaTEM-30, blaTEM-47/68, blaACT) that had never been found in UWTPs were identified in this study. Nine of the identified bla genes had been found in the same environment previously. The blaFOX-15 variant on a Kluyvera sp. plasmid and blaGES type on Raoultella spp. plasmids were observed for the first time in these genera. There was a decrease in the number of multidrug resistant strains in the effluent compared to the influent. Finally, a significantly higher number of cefotaxime and carbapenem unsusceptible strains were detected in the influent than in the effluent. The results strongly support the hypothesis of UWTPs as a hot spot for antibiotic resistant genes (ARGs) and antibiotic resistant bacteria (ARB) accumulation and indicate that β-lactamase genes are widely disseminated among gram-negative rods isolated from this environment.

The removal of diclofenac, which is a widely used non-steroidal anti-inflammatory drug and a dangerous environmental contaminant of surface water, was studied. Its complete degradation by Raoultella sp. KDF8 to primary metabolic products was described with individual metabolites identified by mass spectrometry. The Raoultella strain KDF8 was cultivated with unlabelled and 13C6-labelled diclofenac. A total of 32 compounds were detected as intermediates in diclofenac metabolism by high resolution tandem mass spectrometry. Furthermore, proteomic analysis showed that the presence of diclofenac resulted in the upregulation of 24 enzymes associated with the benzoate, catechol, protocatechuate and ketoadipate pathways. The presence of genes encoding specific enzymes, such as catechol 1,2-dioxygenase, protocatechuate 3,4-dioxygenase and quercetin 2,3-dioxygenase, has been verified by sequence analysis of PCR products. The description of diclofenac metabolism by strain KDF8 provides a detailed view of the degradation of xenobiotic aromatic compounds by microorganisms in general.

Raoultella Planticola is a gram-negative, non-motile, anaerobic bacterium of the Genus Raoultella most commonly found in water, soil, and aquatic environments1 Originally classified as a member of the genus Klebsiella, it was reclassified as Raoultella spp. in 2001 based on 16S rRNA and rpoB gene sequencing.1 This bacterium is a rare source of infection in humans; current literature provides few serious cases. The first Raoultella invasive human infection was found in 1984 in a patient with sepsis.2 Most reported cases since then have been associated with bacteremia. We present a case of R. Planticola in a patient with UTI, as well as a review of prior reported cases of R. Planticola associated with cystitis. There is weak evidence for susceptibility to R. Planticola cystitis; risk factors include immunosuppression, invasive procedures, and contaminated equipment3, 4, 5, Table 2. Table 2 References.

Klebsiella species occupy a wide range of environmental and animal niches, and occasionally cause opportunistic infections that are resistant to multiple antibiotics. In particular, Klebsiella pneumoniae (Kpne) has gained notoriety as a major nosocomial pathogen, due principally to the rise in non-susceptibility to carbapenems and other beta-lactam antibiotics. Whilst it has been proposed that the urban water cycle facilitates transmission of pathogens between clinical settings and the environment, the level of risk posed by resistant Klebsiella strains in hospital wastewater remains unclear. We used whole genome sequencing (WGS) to compare Klebsiella species in contemporaneous samples of wastewater from an English hospital and influent to the associated wastewater treatment plant (WWTP). As we aimed to characterize representative samples of Klebsiella communities, we did not actively select for antibiotic resistance (other than for ampicillin), nor for specific Klebsiella species. Two species, Kpne and K. ( Raoultella ) ornithinolytica (Korn), were of equal dominance in the hospital wastewater, and four other Klebsiella species were present in low abundance in this sample. In contrast, despite being the species most closely associated with healthcare settings, Kpne was the dominant species within the WWTP influent. In total, 29 % of all isolates harboured the bla OXA-48 gene on a pOXA-48-like plasmid, and these isolates were almost exclusively recovered from the hospital wastewater. This gene was far more common in Korn (68 % of isolates) than in Kpne (3.4 % of isolates). In general plasmid-borne, but not chromosomal, resistance genes were significantly enriched in the hospital wastewater sample. These data implicate hospital wastewater as an important reservoir for antibiotic-resistant Klebsiella , and point to an unsuspected role of species within the Raoultella group in the maintenance and dissemination of plasmid-borne bla OXA-48. This article contains data hosted by Microreact.

Klebsiella spp. are a major cause of both nosocomial and community acquired infections, with K. pneumoniae being responsible for most human infections. Although Klebsiella spp. are present in a variety of environments, their distribution in the sea and the associated antibiotic resistance is largely unknown. In order to examine prevalence of K. pneumoniae and related species in the marine environment, we sampled 476 batches of marine bivalve molluscs collected along the Norwegian coast. From these samples, K. pneumoniae (n = 78), K. oxytoca (n = 41), K. variicola (n = 33), K. aerogenes (n = 1), Raoultella ornithinolytica (n = 38) and R. planticola (n = 13) were isolated. The number of positive samples increased with higher levels of faecal contamination. We found low prevalence of acquired resistance in all isolates, with seven K. pneumoniae isolates showing resistance to more than one antibiotic class. The complete genome sequence of cefotaxime-resistant K. pneumoniae sensu stricto isolate 2016-1400 was obtained using Oxford Nanopore and Illumina MiSeq based sequencing. The 2016-1400 genome had two contigs, one chromosome of 5,088,943 bp and one plasmid of 191,744 bp and belonged to ST1035. The &beta, lactamase genes blaCTX-M-3 and blaTEM-1, as well as the heavy metal resistance genes pco, ars and sil were carried on a plasmid highly similar to one found in K. pneumoniae strain C17KP0055 from South-Korea recovered from a blood stream infection. The present study demonstrates that K. pneumoniae are prevalent in the coastal marine environment and that bivalve molluscs may act as a potential reservoir of extended spectrum &beta, lactamase (ESBL)-producing K. pneumoniae that may be transmitted through the food chain.

Raoultella planticola, a gram-negative bacterium, first emerged in late 1900s as Klebsiella planticola. It was later classified as Raoultella genus in 2001. This nonmotile rod is usually found in soil and aquatic environment. There are two known species of Raoultella: R. planticola and R. ornithinolytica. They are responsible for numerous yet rare infections including cystitis, pneumonia, and bacteremia. To date, only one case of joint or bone infection due to R. planticola has been reported. The infection is eradicated after arthroscopic lavage and antibiotic therapy with fluoroquinolones. We present the first case of septic arthritis due to R. planticola involving a native knee joint following synovectomy during arthroscopy.

Background Raoultella are Gram-negative rod-shaped aerobic bacteria which grow in water and soil. They mostly cause nosocomial infections associated with surgical procedures. This case study is the first report of a Raoultella infection in Africa. Case presentation We report a case of a surgical site infection (SSI) caused by Raoultella planticola which developed after caesarean section (CS) and surgery for secondary small bowel obstruction. The patient became febrile with neutrophilia (19,157/µL) 4 days after laparotomy and started to develop clinical signs of a SSI on the 8th day after laparotomy. The patient continued to be febrile and became critically ill despite empirical treatment with ceftriaxone and vancomycin. Raoultella species with extended antimicrobial resistance (AMR) carrying the CTX-M-9 β-lactamase was isolated from the wound discharge. Considering the antimicrobial susceptibility test, ceftriaxone was replaced by ceftazidime. The patient recovered and could be discharged on day 29 after CS. Conclusions Raoultella planticola was isolated from an infected surgical site after repeated abdominal surgery. Due to the infection the patient’s stay in the hospital was prolonged for a total of 4 weeks. It is noted that patients undergoing surgical and prolonged inpatient treatment are at risk for infections caused by Raoultella. The development of a SSI caused by Raoultella planticola with extended AMR has to be assumed to be a consequence of ineffective antibiotic utilization. The presented case advices that rare bacteria as Raoultella should be considered as potential cause of nosocomial SSI with challenging treatment due to high levels of AMR.

Raoultella ornithinolytica is one of the three species of Raoultella. The present case report describes a two-year-old child who had complaints of discomfort and fever, and Raoultella ornithinolytica in his urinary culture. Grade-2 hydronephrosis and a 7.5-mm urinary stone were detected in the patient’s left ureter. The stone was expelled upon consultation with pediatric urology department. The patient was treated according to culture antibiotic sensitivity report and continued to be followed-up., Raoultella ornithinolytica je jedna od vrsta bakterije Raoultella. U ovom prikazu slučaja opisuje se dvogodišnje dijete koje je imalo tegobe i groznicu te bakteriju Raoultella ornithinolytica u urinokulturi. U bolesnikovu desnom ureteru nađena je hidronefroza 2. stupnja i kamenac veličine 7,5 mm. Kamenac je izbačen u konzultaciji s pedijatrijskim urologom. Bolesnik je liječen prema antibiogramu, a njegovo stanje se i dalje prati.

The spread of antibiotic-resistant Enterobacteriaceae in the community is one of the main challenges for antibiotic treatment of community-onset infections. We evaluated the microbiological and molecular characteristics of stool samples from adults with comprehensive health examinations. Of 109 fecal samples, bacterial growth was observed in 86 samples and 61 gram-negative bacterial isolates were identified, of which 45 were Escherichia coli isolates (73.8%). Two isolates of Raoultella showed imipenem resistance, and both E. coli and Citrobacter freundii showed intermediate resistance to imipenem. Colistin resistance was identified in isolates of Klebsiella variicola and Salmonella subterranean, but no isolates carried mcr-1. As for E. coli genotypes, 35 sequence types were identified. blaTEM-1, blaTEM-30, and blaCTX-M were identified in 15, 1, and 4 E. coli isolates, respectively. In addition, all four Klebsiella pneumoniae isolates carried blaSHV. Many genotypes that have been identified in isolates causing human infections were found in isolates in this study. There is a need to control the rise and spread of antibiotic-resistant pathogens by fecal carriage.

Raoultella electrica, a Gram-negative, non-spore-forming, rod-shaped facultative anaerobe, was identified during a regular investigation of bacterial contamination in table eggs in the winter season. A total of 165 hen's eggs were collected in the winter season from 15 different areas of the city of Jaipur, India. Gram-negative Enterobacteriales were isolated on selective and differential media by the conventional plate method and were further identified by several biochemical tests and 16S rRNA gene sequencing. Commonly prescribed antibiotics for enteric infection were used for antibiotic susceptibility testing. For isolated microorganisms, different resistance patterns were found against the different antibiotics used (p

Cerebral abscess is a potentially fatal neurosurgical condition, despite improvements in technology, new antimicrobial agents and modern neurosurgical instruments and techniques. I report the case of a 64-year-old woman, affected by a right frontobasal brain abscess, compressing the homolateral frontal horn of lateral ventricle, with a second mass partially occupying the right orbital cavity. She presented also with inflammatory sinusopathy involving the right maxillary, ethmoid and frontal sinuses. After 14 d of clinical observation and antimicrobial therapy, the patient received a computed tomography scan, which showed growth of the cerebral mass, with a ring of peripheral contrast enhancement and surrounding edema. She promptly underwent neurosurgical treatment and recovered well, except for the sight in her right eye, which remained compromised, as before the operation. This is believed to be the first case of cryptogenic cerebral abscess caused by Raoultella ornithinolityca isolated from the brain, with more than 1-year follow-up.

The genus Raoultella belongs to the family of Enterobacteriaceae. Raoultella spp. are Gram-negative, aerobic, non-motile rods. This genus can be distinguished from the genus Klebsiella, in that genus use histamine as the only source of carbon in the medium. Also, Raoultella grow at 4 °C and do not produce gas from lactose at 44.5 °C. Raoultella sp. is known to inhabit natural environments (water, soil, plants). The reservoir of Raoultella is the gastrointestinal tract and upper respiratory tract. Raoultella spp. are opportunistic bacteria, which usually cause infections of the biliary tract, pneumonia and bacteraemia in oncologic and with lower immunity patients. Raoultella planticola and Raoultella ornithinolytica are the most frequently encountered human pathogens among the genus Raoultella. In this review, the current knowledge on Raoultella infections is summarized.

Infections in humans by Raoultella spp. are rare and the effect that Raoultella spp. might have as a human pathogen is currently unknown. A clinical case is presented of catheter-related bacteraemia caused by Raoultella ornithinolytica, treated successfully with applied antibiotic therapy (intravenous cefepime and sealed the catheter with amikacin).

Leachates generated by solid waste dumpsites could be a factor in the development of antibiotic resistance in environmental bacteria. In Nigeria, there is a dearth of information on the contribution of leachates from dumpsite to the ever-increasing trend of antibiotic resistance. A total of 250 cefotaxime-resistant bacteria recovered from dumpsite leachate was screened for extended spectrum β-lactamase (ESBL) production using the double disc synergy test and 41 were ESBL producers. The ESBL producers belonged to four genera and were identified as Escherichia (20), Citrobacter (13), Enterobacter (6) and Raoultella (2). Antibiotic susceptibility testing was carried out using disk diffusion method, while detection of extended spectrum and AmpC β-lactamase genes was done using Real-Time PCR. All the ESBL- producing bacteria were multidrug resistant, with 100% resistance observed to cefotaxime, cefpodoxime, tetracycline, sulfonamide, ciprofloxacin, ampicillin, ertapenem and imipenem, while 81.6% and 63.1% of the ESBL producers showed resistance to ceftazidime and amoxicillin-clavulanate respectively. blaCTX-M-1 and blaCTX-M-9 groups of CTX-M β-lactamases were detected in 33 (80.5%) of the isolates, while 26 (63.4%) harboured the blaCTX-M-2, blaCTX-M-8 and blaCTX-M-25 groups. blaTEM was detected in 31 (75.6%) of the ESBL producers, while blaSHV was detected in 13 (31.7%). One isolate (E. coli AW-32) carried blaCMY-1 gene. None of the isolates carried blaKPC, blaNDM-1 and blaampC genes, while seven isolates were devoid of any gene. There was co-occurrence of resistance genes in thirty of the isolates. This study has revealed that dumpsite leachates could be important reservoirs of multidrug resistant Enterobacteriaceae harbouring extended spectrum and AmpC β-lactamases genes.

Severe cases of infections caused by Raoultella planticola are constantly being reported from all over the world with the increase in drug-resistance patterns. In this study, we retrospectively evaluated the clinical characteristics of R. planticola infections with patients’ demographics and antimicrobial susceptibilities of the R. planticola isolates. R. planticola isolates were retrospectively evaluated. VITEK 2® automated system was used for identification and antimicrobial susceptibility testing. Verification of the low-discriminated isolates was analyzed with MALDI-TOF method using VITEK MS® system. Gene-Xpert® system was used for detection of bla IMP-1-, bla KPC-, bla NDM-1-, bla OXA-48- and bla VIM-type carbapenemases. The data of the patients with R. planticola infection were collected from hospital records. During the 4-year period, 42 episodes of R. planticola infections were detected. MALDI-TOF was used for 11 of the low-discriminated isolates, and 1 of which identified as R. terrigena was excluded. Carbapenems and aminoglycosides were the most effective antimicrobial agents. Extended spectrum beta-lactamases were detected in seven of the isolates. Three carbapenem-resistant isolates were detected as bla OXA-48-type carbapenemase carrier. Nosocomial R. planticola infections constituted 80.9 % (n = 34) of the infections. Most common infections related with R. planticola were blood stream infections (n = 24) (p 0.005). Challenging infections caused by Raoultella spp., like those of multidrug resistant Klebsiella spp., will probably become a concern for clinicians as well as microbiologists . In literature, there were few cases, but we believe that the incidence of Raoultella spp. infections, which may result from misidentification, are more common than expected , and it is not unlikely that there will be a gradual increase and spread in multidrug-resistant isolates.

The genus Raoultella was excised from Klebsiella in 2001, but difficulties in its identification may have led to an underestimation of its incidence and uncertainty on its pathogenic role. Recently, clinical reports involving Raoultella have increased, probably through the introduction of mass-spectrometry in clinical microbiology laboratories and the development of accurate molecular techniques. We performed a retrospective analysis using our blood culture collection (2011-14) to identify Raoultella isolates that could have been erroneously reported as Klebsiella. PCR and gene sequencing of highly specific chromosomal class A β-lactamase genes was established as the reference method, and compared with 16S rRNA and rpoβ sequencing, as well as matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS), MicroScan Walkaway system and API20E biochemical identification. MALDI-TOF and rpoβ correctly identified all Raoultella isolates, whereas 16S rRNA provided inconclusive results, and MicroScan and API20E failed to detect this genus. The analysis of the clinical characteristics of all Raoultella bacteraemia cases reported in the literature supports the role of Raoultella as an opportunistic pathogen that causes biliary tract infections in elderly patients who suffer from some kind of malignancy or have undergone an invasive procedure. Two salient conclusions are that Raoultella shows tropism for the biliary tract and so its identification could help clinicians to suspect underlying biliary tract disease when bacteraemia occurs. Concomitantly, as most phenotypic identification systems are not optimized for the identification of Raoultella, the use of MALDI-TOF or additional phenotypic tests is recommended for the reliable identification of this genus.

This study sought to investigate and compare bacterial contamination levels at six different sites along the Diep and Plankenburg river systems in the Western Cape, South Africa. Surface water and sediment samples were collected monthly from the six selected sampling sites along both river courses between January 2014 and December 2014 and were evaluated for bacterial contaminants. Microbial isolation, characterisation and identification were done using conventional techniques (serial dilution, Gram staining, and biochemical testing) and molecular identification techniques (polymerase chain reaction and DNA sequencing). A total of 19 bacterial isolates belonging to the genera Raoultella, Bacillus, Pseudomonas, Klebsiella, Escherichia, Enterobacter, Exiguobacterium, Acinetobacter, Serratia, Aeromonas, Staphylococcus and Citrobacter were isolated from the surface water and sediment samples at the end of the survey. Higher microbial load was obtained from sediment samples compared to surface water samples. Seasonal variation was also observed in terms of microbial counts. Higher microbial counts were obtained during summer sampling time compared to winter sampling time. The most contaminated site was located on Plankenburg River with average bacterial counts ranging between 3.1 × 105–6.9 × 108 CFU/ml and 3.9 × 106–2.88 × 109 CFU/ml from surface water and sediment, respectively, recorded at this site during winter and summer. Although lower microbial counts were recorded along the Diep River course, most of the bacterial counts recorded along both rivers exceeded the acceptable maximum limits for river water.

Infection with Raoultella ornithinolytica is rare and normally the infection is present in patients with underlying malignancies or chronic diseases. It is normally treated with antibiotics. In this case report, a neuro-intensive patient without malignancies or other severe chronic diseases was colonized with Pseudomonas aeruginosa but infected with Raoultella ornithinolyca. The patient recovered without treatment with antibiotics.

Genetic diversity often enhances the tolerance of microbial communities against antimicrobial treatment. However the sociobiology underlying this antimicrobial tolerance remains largely unexplored. Here we analyze how inter-species interactions can increase antimicrobial tolerance. We apply our approach to 17 industrially relevant multispecies biofilm models, based on species isolated from 58 contaminating biofilms in three breweries. Sulfathiazole was used as antimicrobial agent because it showed the highest activity out of 22 biofilm inhibitors tested. Our analysis reveals that competitive interactions dominate among species within brewery biofilms. We show that antimicrobial treatment can reduce the level of competition and therefore cause a subset of species to bloom. The result is a 1.2-42.7-fold lower percentage inhibition of these species and increased overall tolerance. In addition, we show that the presence of Raoultella can also directly enhance the inherent tolerance of Pseudomonas to antimicrobial treatment, either because the species protect each other or because they induce specific tolerance phenotypes as a response to competitors. Overall, our study emphasizes that the dominance of competitive interactions is central to the enhanced antimicrobial tolerance of the multispecies biofilms, and that the activity of antimicrobials against multispecies biofilms cannot be predicted based on their effect against monocultures. ispartof: The ISME Journal: multidisciplinary journal of microbial ecology vol:12 issue:8 pages:2061-2075 ispartof: location:England status: published

Made available in DSpace on 2018-12-11T17:24:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-04-01. Added 1 bitstream(s) on 2019-10-09T18:32:06Z : No. of bitstreams: 1 S1516-635X2018000200189.pdf: 150511 bytes, checksum: b0bdba2ae71fc325d8ad9a2341d5bca4 (MD5) Raoultella ornithinolytica is a gram-negative aerobic bacterium belonging to Enterobacteriaceae family, an emerging pathogen that causes several pathogenic conditions in man, with little veterinary importance; however, its identification is underestimated by conventional laboratory techniques. The present study reports the identification of R. ornithinolytica in Tinamus solitaries, during a routine sanitary evaluation of aerobic enterobacteria in cloacal microbiota of birds belonging to the Güira Oga Center, Puerto Iguazu, Argentina. The sample was preliminary classified as Klebsiella spp.; however, after the use of the MALDI-TOF MS technique it was identified as R. ornithinolytica. The sample was submitted to an antimicrobial susceptibility test, where it showed a similar pattern profile as reported in the literature, with resistance to ampicillin and other β-lactam antibiotics. It is possible that Raoultella spp are more common in birds as it is reported. Therefore, review studies on bacteria collections of avian origin, as well as cases with confirmation of Klebsiella, should be deeply evaluated in laboratorial routine, mainly due to the pathogenic potential of R. ornithinolytica for Poultry, as well as for public health. Faculdades Integradas de Ourinhos - FIO, R. Luzia de Masseno Pontes 430, Bairro Jardim Itamaraty Ourinhos Centro Güira Oga Universidade Estadual Paulista - UNESP Instituto Federal de Ciências e Tecnologia do Amazonas - IFAM Universidade de São Paulo - USP Universidade Estadual Paulista - UNESP

Introduction. Raoultella is a genus of aerobic Gram-negative bacilli belonging to the family Enterobacteriaceae that are commonly found in water, soil and aquatic environments. With improved bacterial identification techniques, Raoultella species (namely R. planticola and R. ornithinolytica) have been an increasingly reported cause of infections in humans. Case presentation. An 85-year-old man presented to hospital with a several-week history of left jaw pain and trismus. His medical history was significant for left mandibular osteomyelitis treated 1 year previously with amoxicillin-clavulanate. On admission, a computed tomography scan demonstrated a 2.6×1.7×1.6 cm peripherally enhancing collection surrounding the left posterior mandibular body. Two aspirates of the abscess grew a bacterium belonging to the genus Raoultella, with discordant species identification (R. ornithinolytica versus R. planticola) using two different techniques. A potential source of infection included a left lower molar tooth which was extracted months preceding the original diagnosis of osteomyelitis. Conclusion. This is the first case of mandibular osteomyelitis caused by Raoultella species reported in the literature. In contrast to other forms of osteomyelitis, the pathogenesis of mandibular osteomyelitis involves contiguous spread from an odontogenic focus. Risk factors for mandibular osteomyelitis include a history of fracture, irradiation, diabetes and steroid therapy. This report adds to the growing literature of infections caused by this genus of bacteria, and raises the possibility of this organism’s role in odontogenic infections.

Raoultella planticola is rarely associated with clinical infection, and a limited number of pediatric cases have been reported. Herein we report a case of bacteremia presumptively secondary to bilateral conjunctivitis in an infant caused by R. planticola which was successfully treated with piperacillin-tazobactam. It should be kept in mind that R. planticola can be a pathogen in pediatric age groups. (C) 2017 The Authors. Published by Elsevier Limited on behalf of King Saud Bin Abdulaziz University for Health Sciences. This is an open access article under the CC BY-NC-ND license

We performed a retrospective analysis of clinical and laboratory data over 5 years in a tertiary centre to assess clinical and microbiological characteristics of patients with Raoultella spp. infection. Raoultella spp. were deemed responsible for clinical infections in 57 patients (R. planticola, n = 32 and R. ornithinolytica, n = 25). The most prevalent diagnoses for R. planticola were cystitis (50%; n = 16) followed by bacteraemia and pneumonia (9.4%; n = 3); for R. ornithinolytica, cystitis (36%; n = 9) followed by pneumonia (24%; n = 6). Immunodeficiency was present in 18 patients (56.3%) with R. planticola and in 16 patients (64%) with R. ornithinolytica infection. Of these, 55.6% and 37.5% had diabetes and 27.8% and 18.% were solid organ transplant recipients, respectively. All isolates were sensitive to third-generation cephalosporins, fluoroquinolones and aminoglycosides. Mortality of infections with R. planticola (n = 5; 15.6%) was higher than for R. ornithinolytica (n = 2; 8.0%), but the difference was not statistically significant.

Background Chromosomal class A β-lactamases have been characterized in Raoultella ornithinolytica and Raoultella planticola. The purpose of this study was to characterize that of Raoultella terrigena. Materials and methods The blaTER-1 gene of R. terrigena strain ATCC33257T was cloned (pACter-1) and sequenced. It was then used to detect the bla gene of strains BM 85 01 095 and SB2796. The hypermutable Escherichia coli strain AB1157 mutS::Tn10 was transformed with pACter-1 and mutants growing on plates containing > 2 mg/L ceftazidime were studied. Notably, the impact of mutations only observed in the promoter region on β-lactam resistance was assessed by site-directed mutagenesis experiments. Results R. terrigena strains ATCC33257T and BM 85 01 095 had the same bla gene and deduced protein (TER-1) whereas there were 3 substitutions in those of strain SB2796 (TER-2). Class A β-lactamases TER showed 78%, 69.9% and 38.7% identity with PLA or ORN, TEM-1 and KOXY, respectively. Compared with TEM-1, TER-1 and TER-2 showed 2 particular substitutions, Leu75Pro and Glu240Asn demonstrated to be involved in the inherent β-lactam resistance profile of R. terrigena. TER-1 (pI of 7.6) had a high activity against penicillin G and a significantly low one against amoxicillin. Substitution G/T observed in the -35 region of the blaTER gene harbored by strains growing in the presence of ≥ 2 mg/L ceftazidime was shown to be responsible for this growth. Conclusion TER is a new class A β-lactamase belonging to functional group 2b.

Drug susceptibility testing was carried out using 14 antibiotics in order to identify trends in the antibiotic tolerance of 142 strains of Enterobacteriaceae isolated from horsemeat commercially available for raw consumption (basashi). A comparison of the sensitivity to the 14 antibiotics using the 90% MIC (minimum inhibitory concentration) values (MIC90) showed the strongest tolerance to ampicillin (ABPC) at a concentration of > 128 μg/mL, followed by that to fosfomycin (FOM) at a concentration of 128 μg/mL. When the sensitivity to these antibiotics was examined for each individual genus of tested bacteria, Hafnia spp. exhibited relative tolerance to ceftazidime (CAZ) and ceftriaxone (CTRX) at a concentration of 4 μg/mL and 2 μg/mL, respectively, which was high in comparison to that observed for the other strains. Furthermore, Raoultella spp. and Serratia spp. were found to be highly resistant to tetracycline (TC) at a concentration of 128 μg/mL and 64 μg/mL, respectively. Of the 142 strains of test bacteria, 140 (98.6%) demonstrated resistance to ABPC, with the exception of Hafnia alvei and Klebsiella pneumonia. In addition, a total of eight strains (5.6%), seven Serratia marcescens strains and one Raoultella terrigena strain, were found to be resistant to TC. Furthermore, one strain of Citrobacter freundii exhibited resistance to nalidixic acid (NA), while another displayed resistance to ofloxacin (OFLX) (0.7% each), and one strain (0.7%) each of Enterobacter cloacae, Serratia marcescens and Citrobacter youngae demonstrated resistance to fosfomycin (FOM), streptomycin (SM) and kanamycin (KM), respectively. A single strain of C. freundii was found to be resistant to three antibiotics, ABPC, NA and OFLX. Resistance to two antibiotics was confirmed in 11 strains, including seven strains of S. marcescens and one strain of R. terrigena (a total of eight strains) resistant to ABPC and TC, and one strain each of C. youngae, S. marcescens and E. cloacae resistant to ABPC and KM, ABPC and SM, and ABPC and FOM, respectively. In addition, 128 strains were resistant to the single antibiotic of ABPC alone. Of the 140 strains demonstrating antibiotic resistance, 137 (97.9%) retained the conjugative R-plasmid transfer factor, excluding three strains of S. marcescens. All transfer factors were ABPC and retained by a high proportion of the bacterial groups, with one strain (100%) being resistant to three antibiotics, nine (81.8%) of the 11 strains being resistant to two antibiotics, and 127 (99.2%) of the 128 strains being resistant to a single antibiotic. In addition, we examined ESBL productivity in the 140 strains of bacteria demonstrating drug tolerance; however, no strains exhibited this characteristic. Therefore, further observation is required to ascertain trends in antibiotic-tolerant bacteria.

Raoultella ornitholytica, an environmental organism, has only recently been reported as a cause of infections in humans, and is associated mainly with bacteraemia in elderly patients. Carbapenem resistance is unusual in Raoultella spp. We describe the first paediatric case of blaNDM-1 Raoultella ornitholytica bacteraemia in a preterm neonate that developed three days after hospitalisation. This case report discusses a rare organism that had an unexpected susceptibility profile and caused bacteraemia in a neonate. Treatment options are explored.

The aim of this study was to determine diversity in members of the family Enterobacteriaceae including the beta-lactamase producing isolates associated with the Spanish slug (Arion vulgaris). 81 isolates, each representing a distinct colonial morphotype, were obtained from fecal samples of Spanish slugs and analyzed. Genetically heterogeneous or similar groups were assessed among the isolates by enterobacterial repetitive intergenic consensus (ERIC)-PCR and further characterized by 16S rDNA sequence analysis. Representative strains were allocated to the genera Citrobacter, Raoultella, Escherichia, Klebsiella, Kluyvera, and Buttiauxella. Fifteen isolates, most closely related to Citrobacter freundii and Escherichia coli, displayed an AmpC phenotype, one E. coli isolate showed an ESBL phenotype. These isolates were phenotypically and genotypically characterized by their antimicrobial resistance pattern. Phylogenetic background and multi-locus sequence typing (MLST) of the E. coli isolates were determined. The multi-drug resistant TEM-1 E. coli positive isolate belongs to the phylogenetic group A and ST10. The CMY-2 positive E. coli isolate belongs to the phylogenetic group D and ST117. Our results show that the common garden slug represents an important potential vector of β-lactamase producing Enterobacteriaceae.

Restaurants used to prepare tenderloin beef medallions using different frying parameters in order to satisfy their customers. However, some of those cooking methods are not in accordance with food safety recommendations, because they do not reach internal temperatures recognized as save, in countries such as US, Canada and Brazil. This study aimed to assess the microbial inactivation in tenderloin beef medallions fried to five pre-determined degrees of doneness. Two different frying techniques were investigated, allowing beef pieces to reach the following degrees of doneness: rare, medium-rare, medium, medium-well and well-done. Before thermal processing, tenderloin beef medallions were artificially contaminated with approximately 106 CFU/g of Escherichia coli and the survival of this microorganism and mesophilic total counts were measured using VRBA + MUG and BHI plates, respectively. Bacterial colonies grew on BHI plates were also analyzed by Matrix-Assisted Laser and Time-Of-Flight desorption/ionization mass spectrometry (MALDI-TOF/MS) in order to identify survivors. Results indicated that complete E. coli inactivation was only observed on tenderloin beefs subjected to well-done degree established by both techniques, given that Technique 1 recommended a final heating inside oven after frying. Without this final oven processing, which is not always done in restaurants, more than 2 log CFU/g of viable E. coli were detected. Modeling of the kinetic parameters by GInaFIT revealed a D value (time needed to reduce 90% of the bacterial population) of 1.67 min for Technique 1 and D = 3.81 min for Technique 2 and this difference was associated to the difference of temperatures of olive oil. MALDI-TOF analyses demonstrated high diversity in natural microbiota of tenderloin beef pieces and among the main identified survivor genera was Citrobacter, Enterobacter, Hafnia, Serratia, Raoultella, Bacillus, Lactobacillus, Micrococcus, Pseudomonas, Serratia and Staphylococcus. Pathogens such as Salmonella and Listeria monocytogenes were not found. Based on the results, we recommend the use of high microbiological quality beef for the preparation of tenderloin beef medallions and the validation of frying process considering specific conditions of restaurants, because different degrees of fried may result in different counts and types of bacterial survivors.

Raoultella spp. representatives are Gram-negative capsulated, nonmotile rods. These bacteria are found in the natural environment: plants, water, soil and insects. R. ornithinolytica is one of the three species of Raoultella. R. ornithinolytica is the only species within the genus which has the ability to produce ornithine decarboxylase. Human infections related to R. ornithinolytica are exceedingly rare. The present case report describes catheter-related blood stream infection caused by R. ornithinolytica and successfully treated with antibiotic therapy.

Allovahlkampfia spelaea was identified for the first time in 2009. As a free living amoeba, it has been suggested to be a protective host for some bacterial pathogens against harsh environmental conditions and can transmit them to vulnerable hosts. We aimed in this study to test the interactions between Allovahlkampfia spelaea and some waterborne and foodborne bacteria and unravel if the tested bacteria can survive and multiply inside amoeba. We used a keratitis isolate of Allovahlkampfia spelaea grown in PYG medium containing proteose peptone, yeast extracts, and glucose. We examined amoeba interactions with Methicillin resistant Staphylococcus aureus, Escherichia coli 1, Klebsiella pneumoniae, Enterobacter aerogenes, Citrobacter cloaca, Proteus mirabilis, Raoultella terrigena, Raoultella ornitholytica, Aeromonas hydrophila and Pseudomonas aeruginosa using the co-culture assays. Amoebal survival rate with different bacterial strains were determined. With the exception of Proteus mirabilis that showed decreased survival rates inside amoebal cells, other bacterial isolates could survive and multiply inside Allovahlkampfia spelaea that was associated with decreased survival rates of the amoeba. Particularly, Pseudomonas aeruginosa, Aeromonas hydrophila and MRSA exhibited significantly increased multiplication rates inside amoeba. Our study demonstrated that Allovahlkampfia spelaea may act as a replicative host for pathogenic bacteria with environmental and clinical implications.

Background Raoultella ornitholytica (R. ornitholytica) is a waterborne Gram-negative bacilli increasingly found in hospitals. Multi-drug resistance has been reported, including to carbapenems. Our objective was to identify demographics of R. ornitholytica at Danville Regional Medical Center (DRMC) to determine predisposing factors to infection and potential antibiotic resistance. Methods Cultures positive for R. ornitholytica were identified through DRMC’s electronic medical records (EMR) from 1/2010 to 3/2017. Site of infection, concurrent infections, isolate susceptibilities, prior antibiotic exposure, and appropriateness of treatment were extracted from the EMR. Healthcare associated was defined as occurring in the hospital, nursing home, long-term acute care, or inpatient rehabilitation facility within the past 90 days. Those with diabetes, cancer, and end stage renal disease (ESRD) were qualified as immunosuppressed. Results Thirty-two cases were isolated, of which 20 had associated clinical data. One urine isolate was consistent with colonization. Of the 19 infections, the majority (n = 15) were urinary tract infections (UTIs) and one case each from bronchial washing, heel wound, blood culture, and vulvar lesion. Clinical demographics are shown in Figure 1. Thirteen (65%) had concurrent infections, of which 5 (26%) were co-infected with Enterococcus faecalis, one which was vancomycin resistant. Three had chronic Foley catheters, constituting 20% of the UTIs. Susceptibilities are reported in Figure 2. Prior antibiotic use is shown in Figure 3. Conclusion Most of the isolates from our institution were relatively sensitive, with most resistance to ampicillin. Two isolates were pansensitive, however one case was sensitive only to nitrofurantoin and ertapenem. All isolates which were resistant to cefazolin and ceftriaxone had prior exposure. The elderly and diabetics had the greatest association with infection. A majority of patients had a concurrent infection, which may suggest this as an opportunistic organism. Our findings warrant further studies to better characterize clinical associations and development of resistance in response to prior antibiotic exposure. Disclosures All authors: No reported disclosures.

The genus Raoultella has been separated from the genus Klebsiella in 2001. Two main species are responsible for human infections: R. ornithinolytica and R. planticola. The most frequent infections due to R. planticola include cystitis, pneumonia and bacteremia (mostly in immunocompromised hosts). To date, no joint or bone infection has been reported. We describe the first case of septic arthritis due to R. planticola following an arthroscopy with intra-articular injection of corticosteroids. Evolution was favorable after arthroscopic lavage and antibiotic therapy with quinolones. Raoultella planticola has been described rarely in human infection. It is mainly deemed responsible for cystitis, pneumonia and bacteremia (mostly in immunocompromised hosts) [1, 2, 3]. To our knowledge no case of bone or joint infection has been reported. We described here the first case of infective arthritis due to R. planticola involving a native knee joint following synovectomy and intra-articular injection of corticosteroids during arthroscopy.

Raultella planticola usually invaded immune compromised patients and has been considered a relatively harmless Gram-negative bacteria. We reported a case of a women with a new pancreatic cancer diagnosis that abruptly develop severe sepsis. A Raoultella planticola was yielded in blood cultures. This case suggest Raoultella as pathogen causing life threatening community acquired infection.

A 58-year-old woman presented to eye emergency with a chronic conjunctivitis which was diagnosed by laboratory microbiological testing to be due to the environmental pathogen Raoultella planticola. The organism was sensitive to Chloramphenicol and the patient made a rapid recovery on these drops. This is the first report of this organism infecting the eye.

Item does not contain fulltext A case series of 14 patients with Raoultella bacteremia was compared with 28 Klebsiella oxytoca and 28 Klebsiella pneumoniae bacteremia cases. Forty-three percent of Raoultella bacteremia cases were associated with biliary tract disease, compared to 32% and 22% of patients with K. oxytoca and K. pneumoniae bacteremia, respectively.

Raoultella planticola is a gram-negative bacterium of the Enterobacteriaceae family that is usually found in soil, plant and aquatic environments. It is an uncommon human pathogen and has been associated with cases of bacteremia, pneumonia, urinary tract infections, among others. Here, we present the case of an 85-year-old female that developed nosocomial pneumonia and bacteremia caused by Raoultella planticola. Pertinent microbiological studies detected carbapenemase production codified by the blaKPC gene. The patient was successfully treated with ceftazidime/avibactam and polymyxin. Our case illustrates the pathogenic potential of this organism and highlights the importance of phenotypic and genotypic assays for the appropriate identification of carbapenemase production.

Raoultella planticola is a gram-negative, aerobic, nonmotile mostly found in environments with high prevalence in soil and water. This organism is a very rare human pathogen as only 29 cases of Raoultella planticola-related infections have been reported until 2017, with only 7 cases in the United States. Only 3 cases of urinary tract infection secondary to R planticola have been reported, 1 in a pediatric patient and 2 in adults. In this article, we present a case of R planticola urinary tract infection in a 65-year-old male with immunoglobulin A nephropathy. On investigation, the patient was found to be septic and empirical antibiotic was started for gram-negative coverage. The patient showed remarkable improvement and discharged on oral antibiotic for 7 days. R planticola rarely cause infection in humans, with overall good prognosis.

Raoultella terrigena ATCC 33257, recently reclassified from the genus Klebsiella, is a drinking water isolate and belongs to a large group of non-typeable Klebsiella and Raoultella strains. Using an O-antiserum against a capsule-deficient mutant of this strain, we could show a high prevalence (10.5%) of the R. terrigena O-serotype among non-typeable, clinical Klebsiella and Raoultella isolates. We observed a strong serological cross-reaction with the K. pneumoniae O12 reference strain, indicating that a large percentage of these non-typeable strains may belong to the O12 serotype, although these are currently not detectable by the K. pneumoniae O12 reference antiserum in use. Therefore, we analyzed the O-polysaccharide (O-PS) structure and genetic organization of the wb gene cluster of R. terrigena ATCC 33257, and both confirmed a close relation of R. terrigena and K. pneumoniae O12. The two strains possess an identical O-PS, lipopolysaccharide core structure, and genetic organization of the wb gene cluster. Heterologous expression of the R. terrigena wb gene cluster in Escherichia coli K-12 resulted in the WecA-dependent synthesis of an O-PS reactive with the K. pneumoniae O12 antiserum. The serological data presented here suggest a higher prevalence of the O12-serotype among Klebsiella and Raoultella isolates than generally assumed.

We developed a two-step PCR-based strategy to detect genes encoding OqxAB, allowing a specific assignment of Tn 6010 -associated oqxAB in Enterobacteriaceae . Chromosomal location in this setup was confirmed by hybridization with I- Ceu I-restricted genomes. This approach led us to find that Klebsiella sp. and Raoultella sp. reference strains chromosomally carried oqxAB .