Nosocomial infection and colonization by Klebsiella trevisanii

Raoultella planticola Infection in Urine

Raoultella planticola is a gram-negative, aerobic, nonmotile bacteria that can be found in soil and water. This is a relatively rare organism with few case reports on it and only three reports of R. planticola-induced urinary tract infection (UTI) have been reported. Here we present a case of acute cystitis caused by R. planticola in a woman with atrial fibrillation and recurrent UTIs.

Bacteremic cholangitis due to Raoultella planticola complicating intrahepatic bile duct stricture 5 years post-laparoscopic cholecystectomy: a case report

Background

Raoultella Planticola is a facultative anaerobic, gram-negative, water- and soil-dwelling rod bacterium rarely reported as a cause of human disease. However, the number of reported R. planticola infections is growing, without a concomitant increase in research on the microbe or its pathogenesis. Previous genomic studies demonstrating genetic similarities between R. planticola and Klebsiella pneumoniae suggest that capsule biosynthesis, mucoid phenotype, biofilm production, and lipopolysaccharide (endotoxin) synthesis may all be potential virulence factors of R. planticola. We present a unique case of R. planticola infection of the biliary tract 5 years after biliary surgery in a patient with no previously documented risk factors. We also use in silico techniques to predict virulence factors of R. planticola.

Case presentation

This case report is the first to discuss a R. planticola infection in the biliary tract of late onset post-surgery (5 years) in a Caucasian patient with no previously documented risk factors.

Conclusions

An in-depth search of the current literature did not yield other similar cases of R. planticola infections. Moreover, to the best of our knowledge, our case is the first case of R. planticola isolated from post-endoscopic retrograde cholangiopancreatography (ERCP) as part of biliary sepsis not associated with gastroenteritis. The late onset of the infection in our patient and the results of the in silico analysis suggest that R. planticola may have survived exposure to the host immune system through the creation of an intracellular biofilm or in a non-culturable but viable state (NCBV) for the 5-year period. The in silico analysis also suggests that biofilms, enterobactin, and mucoid phenotype may play a role in the pathogenesis of R. planticola. However, further research is needed to illuminate the significance of pili, capsule biosynthesis, and lipopolysaccharide (LPS) in the virulence of R. planticola. Lastly, as our patient did not have any risk factors previously associated with R. planticola, we suggest that biliary tract stricture, cholecystitis, and prior surgery may be possible novel risk factors.

A Rare Case of Raoultella planticola Urinary Tract Infection in a Patient With Immunoglobulin A Nephropathy

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.

Community-acquired infection to Raoultella ornithinolytica presenting as appendicitis and shock in a healthy individual

Raoultella ornithinolytica and Raoultella planticola are histamine-producing bacteria that are usually found in fish and water. They are associated with scombroid syndrome that presents with vomiting and flushing. A wide range of infections with these germs is reported, but mainly in fragile hospitalized patients with multiple comorbidities. We report the case of a 54-year-old healthy patient who presented with 24-hours abdominal pain, vomiting, flushing and shock. The abdominal examination showed guarding in the right lower quadrant (RLQ), and the abdominal CT scan images showed a thickened terminal ileum and a distended appendix. The patient underwent a surgical exploration revealing a normal terminal ileum but an inflamed appendicular base. Raoultella ornithinolytica was found in blood cultures and in the liquid retrieved from the RLQ. To the best of our knowledge, this is the first report of a severe life-threatening intra-abdominal presentation due to a community-acquired R. ornithinolytica infection.

Raoultella planticola Bacteremia in a Patient with Early Gastric Cancer

The patient was an 81-year-old man who was found to have bacteremia due to Raoultella planticola, which might have entered the circulation through the bile duct during the passing of a gallbladder stone. In the present case, we screened for malignancies because most cases of R. planticola bacteremia occur after trauma, invasive procedures, or in patients with malignancy (70.6%). Early gastric cancer was detected. Although the association between R. planticola bacteremia and malignancy remains speculative in the present case, it may be useful to scrutinize similar cases involving low-virulence bacteremia for possible malignancies or immune conditions.

A case of urinary tract infection caused by Raoultella planticola after a urodynamic study

Here we report the case of a patient who developed urinary tract infection after a urodynamic study. The causative agent was Raoultella planticola, a rare opportunistic pathogen that usually invades immunocompromised patients. While a urinary tract infection with R. planticola has been previously described, this is the first report in which an R. planticola infection developed after a urodynamic study. We postulate that the mechanism of infection was direct invasion of the urinary tract from contaminated urodynamic study equipment. Here, we discuss the role played by isotonic solutions in facilitating bacterial reproduction.

A cardiac implantable device infection by Raoultella planticola in an immunocompromized patient

Introduction. Infection of cardiac implantable electronic devices is a severe condition associated with high mortality, particularly in patients who are dependent upon heart-pacing devices. Staphylococci are found in 70 % of reported cases.

Case presentation. We report the case of a cardiac-pacemaker infection in a 79-year-old man, cumulating a history of rheumatoid arthritis treated by corticosteroids and methotrexate by a recently identified micro-organism: Raoultella planticola. He presented local signs of infection on his VVI pacemaker implantation site and underwent urgent pocket device replacement under cefamandole antibioprophylaxis. On incision thick pus oozed out. It was necessary to perform a complete hardware extraction comprising the pulse generator and the ancient lead. Pus was inoculated into aerobic and anaerobic culture vials and Gram staining unveiled Gram-negative rods. Microbiology analysis identified the organism as R. planticola. A new pacing device was inserted on the contrlateral pectoral region. Ciprofloxacin enabled full recovery. A literature review concerning this pathogen revealed that it is involved in severe infections such as bloodstream infections, peritonitis, cellulitis, pneumonia and lung abscesses, and urinary tract infections. In these case reports, underlying co-morbidities were identified such as solid active neoplasia, recent chemotherapy, corticosteroids, solid-organ-recipient patients and recent open surgery.

Conclusion.R. planticola is a serious emerging pathogen and contributes to the burden of various infectious conditions. Its pathogenicity and occurrence should be known by clinicians and a high level of awareness is necessary to precisely identify it provide the correct antibiotic regimen.

A rare case of Raoultella planticola urinary tract infection in an immunocompromised patient with multiple myeloma

INTRODUCTION

Raoultella planticola is a gram-negative rod associated with soil and aquatic environments that has rarely been associated with human infections.

PRESENTATION OF CASE

We present the case of a 73 year old female with multiple myeloma and recurrent Clostridium difficile infection who was found to have a urinary tract infection with Raoultella planticola, which has only been reported to cause 29 cases of human infections and 2 cases of urinary tract infections.

DISCUSSION AND CONCLUSION

Our case and literature review suggest that immunocompromised patients are predisposed to developing Raoultella planticola infection, and that this is a potential emerging pathogen.

Raoultella spp.-clinical significance, infections and susceptibility to antibiotics

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.

Combination of Tigecycline and Levofloxacin for Successful Treatment of Nosocomial Pneumonia Caused by New Delhi Metallo-β-Lactamase-1-Producing Raoultella planticola

Raoultella planticola is a gram-negative bacterium that rarely causes diseases in humans. Here, we present a case of hospital-acquired pneumonia caused by R. planticola that likely originated in the gastrointestinal tract. To the best of our knowledge, this is the second report describing the detection of the gene New Delhi Metallo-β-lactamase-1 (bla_NDM-1) in multidrug-resistant R. planticola. Clinical samples were collected for bacterial culture and antimicrobial susceptibility testing from a patient during hospitalization. The presence of bla_NDM-1 was detected by PCR and sequencing. An NDM-1-positive R. planticola was isolated from the sputum and stool of the same patient. Further findings confirmed that bla_NDM-1 was located on a plasmid. Isolates from the sputum and stool cultures were identical, suggesting that the R. planticola may have originated in the gastrointestinal tract. The patient completely recovered and was discharged after treatment with tigecycline combined with levofloxacin, for a week. In conclusion, R. planticola is a possibly underestimated pathogen that contributes to the spread of the bla_NDM-1 gene. Early and precise identification of this pathogen can lead to better prognosis of the associated infections and an improved approach to controlling the spread of carbapenemase-resistant gram-negative bacteria.

Fatal pancreatic pseudocyst co-infected by Raoultella planticola: an emerging pathogen

Raoultella planticola is an aerobic Gram-negative bacterium belonging to the Enterobacteriaceae family. Initially identified in the 1980s, its pathogenic potential was further recognized when the first case of bacteremia was reported. Since then, only a few infections caused by this pathogen have been described. Although considered an opportunistic agent, fatal outcomes are associated with the infection by this pathogen, since it is more prevalent among the patients with immunodeficiency. The authors report the case of a middle-aged man diagnosed with end-stage renal disease and alcoholic pancreatitis, who was admitted to the emergency department with septic shock. Physical examination disclosed peritoneal irritation and a laparotomy was undertaken. Purulent peritonitis was found as well as a retroperitoneal abscess, which was drained. The postoperative period was troublesome, and the patient died. The autopsy showed a ruptured, infected pancreatic cyst and purulent peritonitis, among other findings. The culture of the peritoneal fluid and two blood sample sets were positive for R. planticola. The authors call attention to the importance of this emerging pathogen associated with severe gastrointestinal infections.

Infections on the rise: Raoultella spp., clinical and microbiological findings from a retrospective study, 2010-2014

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.

Raoultella planticola peritonitis in a patient on continuous ambulatory peritoneal dialysis

A 65-year-old man on continuous ambulatory peritoneal dialysis was admitted with peritonitis. Empirical antibiotic therapy was initiated, and Raoultella planticola was identified in the peritoneal fluid culture. We treated the patient with intraperitoneally administered ciprofloxacin and ceftazidime according to the antibiotic susceptibility. His condition improved, and he was well treated with a 2-week antibiotic course.

Low virulence? Clinical characteristics of Raoultella planticola bacteremia

PURPOSE

Numerous case reports regarding Raoultella planticola infection have accumulated in the literature; however, its significance as a clinical pathogen remains unknown. We performed a retrospective review of R. planticola bacteremia to characterize its clinical features, antimicrobial susceptibility, and patient outcome.

METHODS

Raoultella planticola bacteremia cases were culled from an electronic database of all bacteremia cases occurring over a 4-year-period. Medical records were retrospectively reviewed and demographic data, clinical findings, presence of underlying disease, results of antimicrobial susceptibility testing, and the antibiotic regimens administered during the treatment were evaluated.

RESULTS

Raoultella planticola was isolated from blood culture specimens in 20 cases. The majority of these patients had underlying malignant conditions (17 patients, 85%). The most prevalent causes of malignancy were adenocarcinoma involving the gallbladder or bile duct (7 patients) and hematologic malignancies (6 patients). No cases with resistance to carbapenem or third generation cephalosporins were found. All 14 patients with R. planticola as the sole microbial isolate recovered with the use of empirical antibiotics. Of the six patients with polymicrobial infection, three did not recover and subsequently expired.

CONCLUSIONS

Raoultella planticola bacteremia seemed to occur mainly in immunocompromised patients, and was also frequently found in patients with lesions involving the gallbladder or bile duct. The overall outcome was favorable when R. planticola was treated with administration of empirical antibiotics. Mixed outcomes were found when blood cultures yielded multiple species of microbes.

Emerging pathogen: a case and review of Raoultella planticola

Raoultella planticola has been considered a relatively harmless Gram-negative bacteria, rarely associated with clinical infection. However, in recent years, the frequency at which severe infection by R. planticola and drug-resistant strains are reported in literature has increased. Here, we present one case of acute cholecystitis caused by R. planticola, and review all previously reported cases of the infection in an attempt to identify new trends in biological and clinical features of R. planticola infections.

Acute prostatitis caused by Raoultella planticola in a renal transplant recipient: a novel case

We present a unique case of acute bacterial prostatitis caused by a very rare human pathogen, Raoultella planticola, in a renal allograft recipient 3.5 months post transplantation. Only a few cases of human infection by this pathogen have been reported worldwide. The present study reports the case of a 67-year-old man who was admitted to our transplant unit 3.5 months post transplantation with fever, dysuria, suprapubic pain, symptoms and signs of acute prostatitis, and elevated markers of inflammation and prostate-specific antigen. R. planticola was isolated in the urine culture. The patient was treated with ciprofloxacin (based on the antibiogram) and had a full recovery, with satisfactory renal function. To the best of our knowledge, this is not only the first reported case of R. planticola prostatitis, but also the first report of such an infection in a solid organ transplant recipient or in a patient on immunosuppressive medication.

Predominant association of Raoultella bacteremia with diseases of the biliary tract

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.

Differentiation of Raoultella ornithinolytica/planticola and Klebsiella oxytoca clinical isolates by matrix-assisted laser desorption/ionization-time of flight mass spectrometry

Ninety-nine clinical isolates previously identified as Klebsiella oxytoca were evaluated using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Eight isolates were identified as Raoultella spp., being 5 Raoultella spp. and 3 K. oxytoca, by 16S rRNA sequencing. These isolates were correctly identified by applying the 10% differential rule for the MALDI-TOF MS score values. This approach might be useful to discriminate Raoultella species from K. oxytoca.

Acute Fatal Peritonitis: A New Organism for Consideration

A 40-year-old man died suddenly and unexpectedly at home. His comorbid conditions included central diabetes insipidus, obesity, and hypertension. Autopsy revealed acute and chronic pancreatitis with an abscess and associated purulent peritonitis. Peritoneal fluid cultures grew Raoultella planticola and a light growth of Candida albicans. The organism isolated, R. planticola, is a waterborne bacterium with limited previous clinical isolates causing morbidity but no previously described mortality. Vitreous humor analysis demonstrated concomitant acute water intoxication complicating the decedent's diabetes insipidus. Discussion includes a review of the literature with a description of the eight previous cases of human infection with R. planticola, a recently described organism that was previously in the genus Klebsiella. The proposed fatal pathogenesis includes retrograde entry of the organism from the gastrointestinal tract via the pancreatic duct to the pancreas and subsequent peritonitis. This is the first reported fatality caused by this organism.

A novel case of Raoultella planticola urinary tract infection

Raoultella species are Gram-negative, non-motile bacilli primarily considered to be environmental bacteria (Bagley et al.; Curr Microbiol 6:105-109, 1981). R. planticola has rarely been documented as a cause of human infections and has never been reported to cause urinary tract infections. We report the first case of R. planticola cystitis.

A Rare Case of Cholecystitis Caused by Raoultella planticola

A 62-year-old female presented with right upper quadrant pain. Clinical examination and ultrasound scan were consistent with gallstones and acute cholecystitis. She received 3 days of intravenous Co-amoxiclav and was discharged with 5-days of oral antibiotics with arrangements to return for an elective cholecystectomy. This was performed 5 months later which revealed an inflamed gallbladder and a localised abscess secondary to gallbladder perforation. Fluid from the gallbladder was taken which cultured Raoultella planticola, a gram-negative, nonmotile environmental bacteria (Bagley et al. (1981)). This is the first report of biliary sepsis with a primary infection by R. planticola. This patient was treated with a 5-day course of oral Co-amoxiclav and made a full recovery.

Necrotizing fasciitis involving the chest and abdominal wall caused by Raoultella planticola

Background

Raoultella planticola was originally considered to be a member of environmental Klebsiella. The clinical significance of R. planticola is still not well known.

Case presentation

We describe the first case of necrotizing fasciitis involving the chest and abdominal wall caused by R. planticola. The identity of the organism was confirmed using 16S rRNA sequencing. The patient was successfully treated with the appropriate antibiotics combined with operative drainage and debridement.

Conclusions

R. planticola had been described as environmental species, but should be suspected in extensive necrotizing fasciitis after minor trauma in mild to moderate immunocompromised patients.

A Rare Case of Soft-Tissue Infection Caused by Raoultella planticola

Raoultella species are Gram-negative, non-motile bacilli primarily considered to be environmental bacteria. Raoultella planticola is a rare cause of human infections. We report a case of serious soft-tissue infection in a young male tiler who presented with cellulitis of his left thumb. He had sustained a crush injury to his left thumb 10 days earlier in a soiled environment. He noted a minor break in the skin and he washed the wound out with running water. One week later, he experienced pain, erythema, and swelling of his thumb and attended his general practitioner who prescribed oral flucloxacillin and penicillin V. Despite this treatment, he noticed progressive erythema and swelling of his thumb requiring hospital admission 3 days later. He underwent washout and debridement of his thumb. Tissue obtained intraoperatively cultured Raoultella planticola. He was treated with broad-spectrum antibiotics including ciprofloxacin and made a full and rapid recovery.

A case of severe pancreatitis complicated by Raoultella planticola infection

A 45-year-old-male presented with severe pancreatitis. Two bacterial isolates obtained from peritoneal fluid and abdominal purulent secretion were identified to the species level by 15 biochemical tests and four supplementary tests as Raoultella planticola. Identification was confirmed by rpoB gene sequencing. R. planticola is difficult to identify in the clinical laboratory, and the clinical significance of this isolation remains uncharacterized. This is the first report of pancreatitis with a primary infection by R. planticola.

Endophytic bacteria inCoffea arabica L

Eighty-seven culturable endophytic bacterial isolates in 19 genera were obtained from coffee plants collected in Colombia (n = 67), Hawaii (n = 17), and Mexico (n = 3). Both Gram positive and Gram negative bacteria were isolated, with a greater percentage (68%) being Gram negative. Tissues yielding bacterial endophytes included adult plant leaves, various parts of the berry (e.g., crown, pulp, peduncle and seed), and leaves, stems, and roots of seedlings. Some of the bacteria also occurred as epiphytes. The highest number of bacteria among the berry tissues sampled was isolated from the seed, and includes Bacillus , Burkholderia , Clavibacter , Curtobacterium , Escherichia , Micrococcus , Pantoea , Pseudomonas , Serratia , and Stenotrophomonas . This is the first survey of the endophytic bacteria diversity in various coffee tissues, and the first study reporting endophytic bacteria in coffee seeds. The possible role for these bacteria in the biology of the coffee plant remains unknown.

Incidence and identification of Klebsiella planticola in clinical isolates with emphasis on newborns

Studies conducted in France and Germany suggest that up to 19% of clinically identified Klebsiella sp. are actually Klebsiella planticola, an environmental species that has been attributed to two cases of septicemia, with a rare isolate of Klebsiella terrigena (0. 4%) being identified. A 1-year survey of newborns on a neonatal ward, also conducted in Germany, reported that 72% of Klebsiella sp. were Klebsiella oxytoca and 8.7% were K. planticola. The tests necessary to identify these species are not found in most clinical identification schemes or in the database matrices of most commercial identification products. To determine the incidence of unrecognized K. planticola among the Klebsiella sp. isolates in our collection, we used the battery of seven supplemental tests amended from the work of Monnet and Freney to test 352 stock isolates and 84 fresh clinical isolates from four local hospitals. After testing 436 strains of Klebsiella, only one strain was identified as a possible K. planticola and none was identified as K. terrigena. We tested an additional 43 stock strains of K. oxytoca isolated from newborns by using eight biochemical tests and found one additional strain of K. planticola. The occurrence of K. planticola in our collection is far less frequent than that observed in other countries.

Identification of clinical isolates of indole-positive Klebsiella spp., including Klebsiella planticola, and a genetic and molecular analysis of their beta-lactamases

In a collection of 43 indole-positive Klebsiella clinical isolates, which were initially identified as Klebsiella oxytoca, there were 18 isolates which exhibited a pattern characteristic of extended-spectrum beta-lactamase (ESBL) resistance. This study aimed to confirm their identity by biochemical tests and by PCR and to determine the genetic basis for their resistance to the beta-lactams and broad-spectrum cephalosporins. Chromosomal beta-lactamase genes were analyzed by PCR, and plasmid-mediated beta-lactamase genes were analyzed by conjugation and transformation. There were 39 isolates which grew on melezitose but failed to grow on 3-hydroxybutyrate, confirming them as K. oxytoca. PCR analysis of their beta-lactamase genes divided these isolates into two groups, the bla(OXY-1) group and the bla(OXY-2) group. Each group had beta-lactamases with different isoelectric points; the bla(OXY-1) group had beta-lactamases with isoelectric points at 7.2, 7.8, 8.2, and 8.8, and the more common bla(OXY-2) group had beta-lactamases with pIs at 5.2, 5.4 (TEM-1), 5.7, 5.9, 6.4, and 6.8. A pI of 5.2 was the most frequently detected and accounted for 59% of all the bla(OXY-2) beta-lactamases. Hyperproduction of clavulanate-inhibited chromosomal beta-lactamases was detected in 17 K. oxytoca isolates, resulting in an ESBL phenotype. K. oxytoca isolates having a plasmid-mediated genetic basis for their ESBL phenotype were not found, confirming that, in K. oxytoca, plasmids are rarely involved in conferring resistance to the newer cephalosporins. Four isolates proved to be isolates of K. planticola in which the beta-lactamase genes failed to react with the primers used in the PCR. One K. planticola isolate contained a transferable plasmid harboring the SHV-5 beta-lactamase gene and showed an ESBL phenotype, while the other non-ESBL K. planticola isolates contained chromosomal beta-lactamases with isoelectric points at 7.2, 7.7, and 7.9 plus 7.2.

Method for differentiating Klebsiella planticola and Klebsiella terrigena from other Klebsiella species

Conventional methods usually fail to identify Klebsiella planticola and Klebsiella terrigena, which represent up to 19% of clinical Klebsiella isolates. By combining four carbon substrate assimilation tests and two conventional tests, the method identified these species with a specificity and a sensitivity of 100%. Overall, sensitivity for Klebsiella identification was 94.7%.

Assessment of the marker value of various components of the coli-aerogenes group of Enterobacteriaceae and of a selection of Enterococcus spp. for the official monitoring of drinking water supplies

The traditional indicators Escherichia coli (in practice currently, though ecologically inaccurately, represented by 'thermotolerant coliforms' at 44 degrees C) and Enterococcus spp. proved to be suitable for the diagnosis of heavy and frequent faecal pollution observed in potentially dangerous waters, especially those originating from karstic aquifers. On the other hand, natural and treated waters, slightly and inconsistently contaminated, occasionally showed a variable Gram-negative flora, difficult to classify by routine tests. In that case, complete identification of isolates may be necessary to ensure a valid decision on the potability of the supply. At any rate some of the Enterobacteriaceae contained in the 'faecal coliform' group and many other 'coliforms', distinct from E. coli, lack sanitary significance although their presence at certain levels may indicate inadequate disinfection, hiatuses in the integrity of the distribution system or both.

Difficulties in identifying Klebsiella strains of clinical origin

Two hundred and four strains of Gram-negative bacteria of clinical origin, initially identified as Klebsiella using the API 20 E system, and 10 reference strains were further analysed with the API 20 EC test system and the API 50 CH, API 50 AO, API 50 AA assimilation systems. Four clusters corresponding to the species Klebsiella pneumoniae subsp. pneumoniae, K. oxytoca, K. planticola, and K. terrigena were formed after numerical analysis of 155 selected tests and the 26 most discriminating tests were determined. A comparison was made between conventional identification using the API 20 E system and the results of the numerical analysis. The conventional method resulted in incorrect identification of 13% of the strains tested, especially for the new species: K. planticola and K. terrigena. After numerical analysis, 17 out of 204 strains (8.3%) of clinical origin were identified as K. planticola. Only 1 strain of clinical origin was identified as K. terrigena, and 1 strain as K. ornithinolytica.

Identification of species and capsular types of Klebsiella clinical isolates, with special reference to Klebsiella planticola

In the 77 reference strains for Klebsiella K types, there are 17 strains (22.1%) of Klebsiella planticola, 6 strains (7.8%) of Klebsiella oxytoca, 1 strain (1.3%) of Klebsiella terrigena, and 53 strains (68.8%) of Klebsiella pneumoniae. The species K. planticola, which was originally isolated from botanical and aquatic environments and hence thus named, was also identified at high incidence (81 strains, 18.5%) among the 439 recent clinical isolates of Klebsiella species. Among these K. planticola strains of hospital origin, 52 (64%) were isolated from sputum, 17 (21%) from urine, and the remaining 12 (15%) from other sources. The capsular types of these isolates were determined by the gel precipitation reaction. Seventy of 81 K. planticola isolates (86.4%) were typable by antisera to Klebsiella reference strains for K types and the K types of the clinical isolates distributed to 35 kinds of K types. The proportion of typable strains among clinical isolates of K. planticola was very similar to those in K. pneumoniae (87.5%) and K. oxytoca (86.0%).