An investigation into the incidence and sources of klebsiella infections in hospital patients

A simultaneous outbreak on a neonatal unit of two strains of multiply antibiotic resistant Klebsiella pneumoniae controllable only by ward closure

Two aminoglycoside-resistant strains of Klebsiella pneumoniae caused an outbreak on the neonatal unit at St Thomas' Hospital. One, which affected 18 patients, was capsular type K18 and resistant to newer cephalosporins by the production of the extended-spectrum beta-lactamase SHV-2; the other, which colonized four patients, was capsular non-typeable and did not produce extended-spectrum beta-lactamase. Both strains were probably brought into the unit by carrier patients; the probable carrier of the non-typeable strain was transferred from another hospital but was negative on a single admission screen; the probable carrier of the K18 strain was not screened on admission because he had been born at St Thomas', but his mother had been transferred from another hospital. Despite intensive efforts to control the outbreak by standard methods of hand washing, screening, patient isolation and environmental cleaning, a total of 22 neonates on the unit eventually became colonized or infected. One of three patients with bacteraemia died. A small proportion of samples of expressed breast milk, electronic thermometers and oxygen saturation probes were contaminated by the K18 strain and may have contributed to some of the cross-infection, but this did not explain the extent of the outbreak. The outbreak was controlled only by opening a temporary ward for colonized neonates and another for newly born babies, which allowed the closure and cleaning of the main neonatal unit. Multiply antibiotic resistant klebsiellas may be highly epidemic and cause serious, difficult-to-control outbreaks on neonatal units. All patients, regardless of their admission history, should be screened on admission for carriage of multiply resistant enterobacteria by a sensitive method, and units should have plans for temporary ward closure should outbreaks occur.

Mopping up hospital infection

Hospital cleaning is a neglected component of infection control. In the UK, financial constraints have forced managers to re-evaluate domestic services and general cleaning has been reduced to the bare minimum. Services have been contracted out in some hospitals, which has further lowered standards of hygiene. Control of infection personnel believe that cleaning is important in preventing hospital-acquired infections but they do not manage domestic budgets and have failed to stop their erosion. It is difficult to defend high levels of hygiene when there is little scientific evidence to support cleaning practices. This review examines the common micro-organisms associated with hospital-acquired infection and their ability to survive in the hospital environment. It also describes studies which suggest that comprehensive cleaning disrupts the chain of infection between these organisms and patients. It is likely that restoring hygienic standards in hospitals would be a cost-effective method of controlling hospital-acquired infection. Furthermore, good cleaning is achievable whereas the enforcement of hand washing and good antibiotic prescribing are not.

Somatic serogroups, capsular types, and species of fecal Klebsiella in patients with ankylosing spondylitis

The purpose of the present study was to find out whether patients with ankylosing spondylitis (AS) carry fecal Klebsiella strains that belong to serotypes or species specific for AS. Somatic serotypes (O groups), capsular (K) serotypes, and biochemically identified species were determined for fecal klebsiellae isolated from 187 AS patients and 195 control patients. The controls were patients with fibromyalgia or rheumatoid arthritis. The 638 isolates of Klebsiella that were obtained represented 161 strains; 81 from AS patients and 80 from the controls. The average number of Klebsiella strains per patient was 1.7 for the AS group and 1.5 for the control group. The most common O group was O1, which was observed for isolates from 23 of 187 AS patients and 24 of 195 control patients. Next in frequency was group O2, which was observed for isolates from 17 AS patients and 15 control patients. Regarding the K serotypes, 59 different types were identified, revealing a heterogeneous representation of Klebsiella strains, without a predominance of any serotype. By biochemical identification, Klebsiella pneumoniae was the most frequently occurring species, being found in 45 AS patients and 45 control patients. Next in the frequency was K. oxytoca, which was observed in 26 AS patients and in 29 control patients. K. planticola and K. terrigena occurred in only a minority of patients. Altogether, when analyzed either separately or simultaneously according to O groups, K serotypes, and biochemically identified species, no evidence of the existence of AS-specific Klebsiella strains was obtained. These findings do not indicate participation of Klebsiella in the etiopathogenesis of AS.

Use of plasmid analysis to determine the source of bacterial invasion of the urinary tract

Gram negative colonisation and infection of the urinary tract is a well recognised complication of the neuropathic bladder caused by spinal cord injury (SCI). K. pneumoniae accounts for one third of all urinary tract infections in hospitalised SCI patients. Plasmid analysis has been shown to reliably fingerprint bacterial strains, particularly K. pneumoniae, so that growth from two separate locations in or on the body can be accurately analysed as to migration from a reservoir to a target location. Eighty seven hospitalised SCI patients on intermittent catheterisation for a total of 586 patient-weeks were studied. Twice weekly catheterised urine specimens and once weekly rectal swab cultures were taken from each patient. Thirty seven patients experienced at least one clinically significant (colony count greater than 10,000/mL) urinary tract colonisation caused by K. pneumoniae, representing 66 total colonisations. Further analysis of 31 of these 37 patients revealed: K. pneumoniae in all of their stool cultures (p less than 0.05) and the identical strain of K. pneumoniae in the urine as well as the stool in 72% of the 66 colonisations (p less than 0.05). Analysis of 14 patients without K. pneumoniae urinary colonisations showed absence of faecal K. pneumoniae in 3, and predominant growth in only 4. In 22 of the 37 patients, multiple K. pneumoniae urinary colonisations were noted, representing 27 pairs of colonisation. Fifteen of the pairs were found to be relapsing (caused by two identical bacterial strains), and 12 were recurrent (caused by two different bacterial strains). Thirteen of the 15 relapsing pairs also had identical urine and stool K. pneumonia strains (p less than 0.05). All colonisations were treated with appropriate antibiotics based on culture and sensitivity reports. Fourteen of the 15 relapsing colonisation pairs have identical antibiograms (p less than 0.05), while all 12 of the recurrent colonisation pairs had different antibiograms (p less than 0.05). The differences noted on sensitivity patterns (antibiograms) correlated with differences among strains of K. pneumoniae based upon plasmid analysis. Treatment of bacteriuria did not affect the nature of repeated colonisations regardless of the antibiotic chosen, the route of administration or the duration of treatment.

Cytotoxic component(s) of Klebsiella oxytoca on HEp-2 cells

A cytotoxic component(s) was detected in culture filtrates of Klebsiella oxytoca isolated from patients with antibiotic-associated hemorrhagic colitis. Eleven of 12 isolates exhibited cytotoxicity on HEp-2 cells. The cytotoxic activity of K. oxytoca strain MH43-1 was stable for the treatment of 60 C for 30 min, but inactivated by the treatment of 100 C for 15 min. This cytotoxicity was not destroyed by the treatment with trypsin or pronase, and the component was filtrable through a membrane filter which cut off molecular weight 5,000.

Comparison of biochemical and serological typing results and antimicrobial susceptibility patterns in the epidemiological investigation of Klebsiella spp

An analysis of the serological and biochemical typing results of 925 clinical isolates of klebsiella revealed that biotyping and serotyping of klebsiella could replace each other for epidemiological purposes. The combination of both typing methods provided even more epidemiological information in analysing clusters of particular serotypes and biotypes in time. Clustering serotypes, mainly of neonatal origin, were nearly uniformly more resistant to the antibiotics in common use than other serotypes. Biotyping as well as serotyping of klebsiella isolates recovered from environmental surveys in the neonatal ward showed that epidemic and non-epidemic klebsiella isolates could occasionally be cultured from the environment and from the staff.

Combined use of phage typing, enterococcinotyping and species differentiation of group D streptococci as an effective epidemiological tool

Ninety-five group D streptococcal isolates from the feces of 95 healthy persons were compared with 157 group D streptococcal isolates from 38 patients of the surgical intensive care unit (sICU). The typing systems consisted of phage typing, enterococcinotyping and species differentiation. Strains isolated from fecal specimens showed high individuality (66 combination types) whereas strains from the sICU revealed strongly uniform types (32 combination types, three types comprised 83 isolates, i.e. 52.8%). Endogenous colonization was demonstrated by isolation of strains from different locations (throat, trachea, wounds, blood, urine, drains, catheters, and vaginal swabs) from the same patient, and routes of transmission of the same strains to several patients were traced. The combination of three systems revealed a good discrimination between isolates of fecal and extrafecal specimens. The investigation detected highly preferred types in strains of extrafecal origin which were rarely isolated from fecal specimens. This may indicate that only strains with special characters preferably were able to colonize extraintestinal sites.

Comparative investigations of Klebsiella species of clinical origin: plasmid patterns, biochemical reactions, antibiotic resistances and serotypes

A total of 124 K. pneumoniae and 52 K. oxytoca isolates obtained from clinical specimens was investigated for plasmid patterns, biochemical reactions, antibiotic resistances and serotypes regarding to the distribution and relationships of these characters. A great diversity of plasmid patterns, bio/serotypes and resistance patterns was revealed. About 90% of strains contained plasmid DNA and up to seven plasmid bands per isolate could be shown. For K. pneumoniae, serotype 7 and for K. oxytoca, type 55 were most common. In general, little difference between both species was found and characters were similarly distributed. With respect to the site of isolation, serotype 7 was predominating in K. pneumoniae strains from the respiratory tract. Highly multiple-resistant organism were found in the largest number in specimens from the urogenital tract, in the lowest in specimens from wounds. Extensive statistical analyses did not detect any relationship among the characters investigated.

Biochemical and serological investigations on clinical isolates of klebsiella

A series of 925 clinical isolates of klebsiella was examined by serological and biochemical typing. To perform serological typing (capsular swelling) 77 capsular antisera were prepared, tested against the type strains and grouped in 13 pools. With this serotyping method 80% of the cultures were typable and 63 distinct types could be recognized. All strains were typable biochemically by means of the numerical coding system of the API-20E system supplemented by digits derived from 15 additional conventional biochemical tests. With the API-20E system 24 different biotypes could be distinguished whereas the combination of API-20E and the 15 additional tests produced 93 biotypes. Maximum discrimination of strains was achieved by the combination of serological and biochemical typing (256 bioserotypes). The reproducibility, typability and discriminating power of the biotyping system was not inferior to serotyping. For epidemiological purposes biotyping can replace serotyping of Klebsiella species, especially in laboratories less well equipped.

Plasmid-specified aminoglycoside-modifying enzymes in clinical isolates of Klebsiella pneumoniae

In 106 clinical isolates of multiresistant Klebsiella pneumoniae strains, we found that aminoglycoside-resistance was due mostly to two adenylating enzymes: AAD (2") (56.6%), that modifies gentamicin, kanamycin, tobramycin and sissomicin, and AAD (3") 9 (56.6% + 19.8%) that modifies streptomycin and spectinomycin. The identification of these enzymes was possible by MICs determination against a set of aminoglycosides antibiotics. AAD (2") + AAD (3")9 were coded by conjugative plasmid of about 120 Md.

The epidemiology of nosocomial infections caused by Klebsiella pneumoniae

Klebsiella pneumoniae causes serious epidemic and endemic nosocomial infections. We conducted a literature review to characterize the epidemiology of epidemic K. pneumoniae outbreaks. Eighty percent of the outbreaks (20/25) involved infections of the bloodstream or urinary tract. Person-to-person spread was the most common mode of transmission, and nearly 50% of the outbreaks occurred in neonatal intensive care units. No one serotype predominated, and no association was found between serotype and either the site of infection or antimicrobial susceptibility pattern. We used data reported to the Centers for Disease Control (CDC) by hospitals participating in the National Nosocomial Infections Study (NNIS) to describe the epidemiology of endemic K. pneumoniae infections. In the 8-year period from 1975 through 1982 the nosocomial K. pneumoniae infection rate was 16.7 infections per 10,000 patients discharged. The rate of infection at medical school-affiliated hospitals was significantly greater than at nonaffiliated hospitals; furthermore, the rate of infection at large affiliated hospitals was greater than at small affiliated hospitals. The rate of infection varied by service, with the highest rate found on the medicine service. During the 8-year period, 184 deaths were caused by nosocomial K. pneumoniae infections (184 deaths/16,969 infections, case-fatality ratio 1.1%), with higher ratios in pediatrics (5%) where there was a 12% mortality in children infected with an aminoglycoside-resistant strain.

New, simple medium for selective recovery of Klebsiella pneumoniae and Klebsiella oxytoca from human feces

A culture medium was developed which selectively favored the growth of Klebsiella pneumoniae and Klebsiella oxytoca in Escherichia coli-rich fecal cultures, without the use of antibiotics. The discriminative capacity of this medium was based on the presence of only two carbon sources, citrate and inositol, which can be utilized by nearly all K. pneumoniae and K. oxytoca strains but not by E. coli. The medium consisted of Simmons citrate agar (SCA) with 1% inositol (SCAI). Klebsiella strains from fecal samples subcultured on SCAI grew unhampered as yellow, dome-shaped, often mucoid colonies, whereas E. coli appeared as tiny, watery colonies. Apart from some Enterobacter strains, no other types of bacteria were found to mimic the typical appearance of klebsiellae. Recovery experiments from stool samples revealed a limiting ratio of Klebsiella to E. coli of 1:10(6) or more when samples were plated on SCAI versus ratios of 1:10(2) to 1:10(3) on blood agar or Macconkey agar. Compared with an existing Klebsiella culture method, the combination of SCA and MacConkey-inositol-carbenicillin (MIC) agar, Klebsiella yields with SCAI were not lower than those with the combination of MIC and SCA. Furthermore, the efficiency of the SCAI method was twice that of the latter combination. The SCAI plate could be a valuable tool in studies on the epidemiology of K. pneumoniae and K. oxytoca, for example in nosocomial infections, especially those concerning immunocompromised patients.

Attempt to modify klebsiella carriage in ankylosing spondylitic patients by diet: correlation of klebsiella carriage with disease activity

Patients with ankylosing spondylitis were asked to follow a 'klebsiella exclusion diet' for 5 months of a 10-month study. The same percentage of faecal samples were positive for klebsiella whether the patients were on or off the experimental diet. The diet also failed to influence variability of klebsiella serotypes. We found no correlation between acquisition of klebsiella and deterioration of disease symptoms, as recorded by the patients. Furthermore, carriage of klebsiella did not correlate with any of the following parameters of disease activity measured in the outpatient clinic: morning stiffness, pain measured on a visual analogue scale, analgesic consumption, ESR, total serum IgA. We found no evidence, therefore, that faecal klebsiella is involved in disease exacerbations of ankylosing spondylitis.

Comparison of different methods for bacteriocin typing of Klebsiella strains

Epidemiological analysis of Klebsiella strains from nosocomial infections needs a simple, stable and reproducible technique of typing. We have evaluated three bacteriocin typing methods for Klebsiella spp. by means of 15 bacteriocin-producing strains, with special reference to stability and reproducibility. With the three methods indicator strains and clinical strains were retyped on different days under constant test procedures. Stability of bacteriocins was tested by titration immediately after preparation and after 4 weeks of storage at -70 degrees C. Thereafter, reproducibility of typing was tested by means of these freshly prepared bacteriocin lysates and of portions of the same lysates stored at -70 degrees C. A moderate reproducibility was obtained with one method after two typing experiments: 79.2% and 61.3% for indicator strains and clinical strains respectively. The other two methods gave a much lower reproducibility of 38.5% and 32.5% for indicator strains and of 11.1% and 25.5% for clinical strains after two experiments. The reproducibility decreased after retyping three, four or five times. These methods are simple to perform but their usefulness for epidemiological studies is doubtful. Possible causes of the lack of reproducibility of the methods are discussed.

An investigation into the properties of klebsiella strains isolated from ankylosing spondylitis patients

Thirty-nine strains of klebsiella isolated from ankylosing spondylitis patients were examined by the methods of Cowan & Steel (1974), those described by Edmondson et al. (1980) and by capsular typing. No significant difference was detected by any of these methods between these strains and those examined by other workers from non-ankylosing spondylitis patients and other environments.

Comparative epidemiology of gentamicin-resistant enterobacteria: persistence of carriage and infection

During a two-year period from January 1979, 260 patients have been involved in an outbreak of carriage and infection due to gentamicin-resistant enterobacteria. We have examined the duration of carriage of such enterobacteria and have compared the carriage of Klebsiella with that of other resistant enterobacteria. Carriage of gentamicin-resistant enterobacteria occurred most frequently and was least sporadic in the intestinal tract. Vaginal carriage was observed in 49 out of 68 patients tested and occurred more frequently in older patients. Oral carriage was noted in 36% of patients but was more sporadic than intestinal carriage. Rates of oral carriage were greater among moribund patients. Carriage at skin sites was related to their proximity to the perineum. Intestinal carriage of gentamicin-resistant Escherichia coli and Klebsiellae but not Klebsiella oxytoca nor Citrobacter persisted for long periods (half lives of 140 and 100 days respectively). Cessation of carriage of gentamicin-resistant Klebsiellae was due to loss of both the organism and its plasmid rather than a shedding of the plasmid. Chronic bacteriuria with gentamicin-resistant E coli and Klebsiellae (half life 180 days) but not Klebsiella oxytoca nor Citrobacter persisted for long periods.

A sequential study of the relationship between faecal Klebsiella aerogenes and the common clinical manifestations of ankylosing spondylitis

An 8-month sequential study at 4-weekly intervals of faecal Klebsiella aerogenes and clinical activity of ankylosing spondylitis is described. Similar frequencies of faecal K. aerogenes were found in the 44 patients and 36 healthy controls studied. Eighteen patients on 19 occasions had K. aerogenes cultured from their faeces, when the preceding specimen had been negative. Six (31.6%) of these occasions were associated with a deterioration in clinical state compared with a similar deterioration associated with only 17 (9.8%) of the remaining 174 faecal culture sequences (p less than 0.02). These results suggest that clinical deterioration in ankylosing spondylitis may be associated with the acquisition of faecal K. aerogenes.

Secretory IgA: immune defence pattern in ankylosing spondylitis and klebsiella

Saliva secretory IgA (sIgA), secretory component (SC); serum immunoglobulins (IgG, IgA, IgM), complement (C3, C4), C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were performed in 32 patients with ankylosing spondylitis and 29 normal controls. They were investigated for carriage in the faeces of Klebsiella spp. on 3 occasions over the previous months. Throat swabs and urine were cultured at the same time as immunological estimations were done. 24-hour urine sIgA specimens were studied in 13 patients and 12 normal controls. Significantly raised mean values of saliva sIgA and serum IgG, IgA, C3, and C4 were found in patients with raised values of serum ESR and CRP levels when correlated with controls. Raised values of sIgA in saliva, which is an important factor of the local immune defence mechanism of mucosal surfaces, suggests the presence of an antigenic stimulus from the gastrointestinal system in ankylosing spondylitis during activity of disease.

Klebsiella neonatal injections: mechanism of broadening aminoglycoside resistance

Kanamycin resistance in eight strains of Klebsiella pneumoniae isolated during an outbreak of infection in a neonatal intensive care unit was found to be transferable and mediated by neomycin phosphotransferase. After gentamicin was used to control infections caused by kanamycin-resistant organisms, a strain resistant to gentamicin emerged. Gentamicin resistance in this ninth strain was not transferable and was accompanied by resistance to tobramycin, amikacin, and streptomycin. Enzymatic modifications of aminoglycosides other than neomycin and kanamycin could not be demonstrated either by filter binding assays or by electrophoresis of a radioactive aminoglycoside substrate. The strain with broad aminoglycoside resistance contained six plasmid deoxyribonucleic acid bands, none of which appeared to be different in molecular weight from plasmid deoxyribonucleic acid bands in strains isolated before the institution of gentamicin therapy. The broadening of resistance was accompanied by reduced uptake of radioactively labeled streptomycin and gentamicin. The relationship between aminoglycoside resistance and reduced drug transport in the absence of any enzymatic modification is discussed.

A comparative study of gram-negative aerobic bacilli in the faeces of babies born in hospital and at home

Examination of the faeces of 50 babies born at home showed that bottle-fed babies carried significantly more Klebsiella, Proteus and Pseudomonas spp. and antibiotic-resistant Escherichia coli than did breast-fed babies. Bottle-fed babies born in hospital had a less mixed faecal flora than bottle-fed babies born at home. The possibility that bacterial contamination of home-prepared feeds may account for these differences requires investigation.

Klebsiella species in hospital food and kitchens: a source of organisms in the bowel of patients

Hospital food was examined for the presence of Klebsiella species. Salads and cold meat were most frequently contaminated, often containing more than 10(3) organisms per g. Klebsiella species were also widely distributed in the kitchen environment which was considered, at least in part, to be the source of the organisms in food. By the use of serological and bacteriocin typing, intestinal carriage of strains ingested in food could be demonstrated.

Further studies on the sources of Klebsiella aerogenes in hospital patients

We report an investigation into faecal carriage of Klebsiella aerogenes and the distribution of this organism in the environment of three wards. In all three wards faecal carriage rates were high (60-70%). The faecal carriage rate increased with antibiotic administration and with length of in-patient stay. K. aerogenes was widely distributed in the ward environment and was found on the hands of nursing staff. Clusters of isolations of K. aerogenes of the same serotype were demonstrated indicating either patient-to-patient transfer or a common source of infection. The results indicate that even under conditions in which there are no outbreaks of K. aerogenes infection, there is a large reservoir of this organism both in the bowel of patients and in the ward environment.

Specific immunoglobulin responses after varicella and herpes zoster

The indirect immunofluorescence technique has been used to titrate the specific immunoglobulins in 200 sera from 64 patients with varicella, and 195 sera from 67 patients with herpes zoster. IgG and IgM antibodies were detected in all patients with varicella, and IgA in 59 (92%). All three classes of antibody appeared 2--5 days after the onset of the rash, increased virtually simultaneously and reached maximum titres during the second and third weeks. IgG then declined slowly, but never became undetectable and was still present in five subjects who were retested after 2--4 years; it was present in 88 out of 100 healthy young adults and probably persists indefinitely after varicella. IgA and IgM antibodies declined more rapidly and were not detected in specimens taken more than a year after the illness. IgA, however, may possibly persist in some cases since low titres were found in 8 out of 88 young adults who possessed IgG antibody and had presumably had varicella in the past. IgA responses were significantly weaker in children under the age of 6 years than in older children and adults. Six out of 67 patients with zoster were tested at various times before the onset of the rash: IgG antibody was detected in all. IgG was present in all sera taken after the onset of the rash, increased rapidly after 2--5 days, reached maximum titres during the second and third weeks and then declined slowly. IgA antibody was detected in 66 patients (99%) and IgM in 52 (78%); both types of antibody followed transient courses, as in varicella. Maximum titres of IgG and complement-fixing antibodies were greater after zoster than after varicella, but the differences were not significant. IgA and IgM titres in young adults with zoster were significantly lower than in older patients, and also lower than in young adults with varicella. Increases in varicella-zoster antibody in patients with herpes simplex virus infections consisted mainly of IgG, sometimes IgA, but never IgM.