agar and Klebsiella-Infections

Carbapenem-resistant K pneumoniae (CRKP) clinical isolates have spread widely now-a-days throughout the world. This study was designed to investigate the carbapenem resistance among Klebsiella pneumoniae and to see anitimicrobial susceptibility of these CRKP isolates to other antimicrobials in a tertiary care hospital in Bangladesh. K pneumoniae was detected by standard methods and various biochemical tests like Triple Sugar Iron (TSI) agar media, Simmons citrate agar media and Motility-Indole-Urea (MIU) agar media. Imipenem resistance was used as the indicator for carbapenem resistance. Agar dilution method was used to determine MIC of imipenem. CRKP were tested for their antimicrobial susceptibility by Kirby-Bauer modified disc-diffusion technique as per Clinical and Laboratory Standard Institute (CLSI) guidelines and United States Food and Drug Administration (FDA) guidelines. Total 75 K pneumoniae were isolated. Among the isolated K pneumoniae, 28(37.33%) were resistant to carbapenem. Most of the CRKP were recovered from intensive care unit. MIC of CRKP ranged from ≥32μg/ml to ≤4μg/ml. Most of the CRKP were resistant to other antimicrobials. Carbapenem resistance in K pneumoniae is increasing in Bangladesh, which is very alarming and we should give importance on standard guideline of antimicrobials use.

Topics: Agar; Anti-Bacterial Agents; Bangladesh; beta-Lactamases; Carbapenems; Humans; Imipenem; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Tertiary Care Centers

Little is known regarding outcomes and optimal therapeutic regimens of infections caused by Klebsiella pneumoniae carbapenemase-producing Klebsiella pneumoniae (KPC-Kp) resistant to ceftazidime/avibactam (CZA) and susceptible to meropenem (MEM). Although susceptible to MEM in vitro, the possibility of developing MEM resistance overtime is a concern. We describe the clinical characteristics of patients with colonization/infection due to KPC variants with a focus on the in vitro activity of fosfomycin (FOS)-containing combinations.. Patients with colonization/infection due to a KPC variant were included. Fosfomycin susceptibility was performed by agar dilution method. Synergistic activity of FOS-based combinations was evaluated by gradient strip-agar diffusion method. The emergence of in vitro MEM resistance was also tested.. Eleven patients were included: eight with infection [four with ventilator-associated pneumonia and four with bloodstream infections] and three with colonization. Previous therapy with CZA was administered to all patients (with a mean cumulative duration of 23 days). All subjects with infection received meropenem, in monotherapy (n = 4) or with amikacin (n = 2) or fosfomycin (n = 2), and achieved clinical cure. A new CZA-susceptible and MEM-resistant KPC-Kp strain was subsequently isolated in three patients (27.3%). Meropenem/vaborbactam (MVB) showed high in vitro activity, while FOS+MEM combination was synergistic in 40% of cases. In vitro resistance to MEM was observed with maintenance of CZA resistance.. Detection of KPC variants may occur within the same patient, especially if CZA has been previously administered. Although clinical success has been obtained with carbapenems, the emergence of MEM resistance is a concern. Fosfomycin plus meropenem is synergistic and may be a valuable combination option for KPC variants, while MVB may be considered in monotherapy. The detection of KPC variants in an endemic setting for KPC-Kp represents a worryingly emerging condition. The optimal therapeutic approach is still unknown and the development of meropenem resistance is of concern, which may lead to therapeutic failure in clinical practice. In these cases, the addition of fosfomycin to meropenem, or a more potent antibiotic, such as meropenem/vaborbactam, may be valuable therapeutic options.

Topics: Agar; Ceftazidime; Fosfomycin; Humans; Klebsiella Infections; Klebsiella pneumoniae; Meropenem

Hypervirulent Klebsiella pneumoniae strains (hvKp) can cause invasive community-acquired infections in healthy patients of all ages. In this study, the prevalence of putative hvKp in a German tertiary center was investigated and hvKp were characterized by phenotypic and molecular assays. All K. pneumoniae isolates in routine microbiological diagnostics from a single center were screened by string-testing over a period of 6 months. String-test positive (≥ 0.5 mm) isolates were re-evaluated on different media and under various conditions (aerobe, anaerobe). For string-test positive isolates, genes (magA, iutA, rmpA and rmpA2) associated with hypermucoviscosity and hypervirulence were amplified by multiplex PCR. PCR-positive isolates were subjected to whole-genome sequencing and sedimentation and biofilm formation assays. From 1310 screened K. pneumoniae isolates in clinical routine 100 isolates (7.6%) were string test positive. From these, 9% (n = 9) were defined as putative hvKp (string-test+/PCR+). Highest rate of string-test-positive isolates was observed on MacConkey agar under aerobic conditions. Amongst these nine putative hvKp isolates, the international lineage ST23 carrying hvKp-plasmid pKpVP-1 was the most common, but also a rare ST86 with pKpVP-2 was identified. All nine isolates showed hypermucoviscosity and weak biofilm formation. In conclusion, 9% of string-positive, respectively 0.69% of all K. pneumoniae isolates from routine were defined as putative hypervirulent. MacConkey agar was the best medium for hvKp screening.

Topics: Agar; Anti-Bacterial Agents; Humans; Klebsiella Infections; Klebsiella pneumoniae; Multiplex Polymerase Chain Reaction; Virulence; Virulence Factors

This study evaluates whether the rapid fosfomycin resistance (fosfomycin NP) method can be used for detecting fosfomycin resistance in routine laboratory work. Results from the disk diffusion and rapid fosfomycin NP methods were compared with the reference agar dilution method for Escherichia coli and Klebsiella spp. strains isolated from urinary tract infections. The study included 57 E. coli and 48 Klebsiella spp. isolates from urinary tract infections. The reference agar dilution and disk diffusion methods were performed in accordance with EUCAST recommendations, and the results were evaluated according to EUCAST V.10.0. The method developed by Nordmann et al. was used for rapid detection of fosfomycin resistance (Nordmann, P., Poirel, L., Mueller, L., 2019. Rapid Detection of Fosfomycin Resistance in Escherichia coli. J Clin Microbiol. 57(1), e01531-18. doi:https://doi.org/10.1128/JCM.01531-18). The acceptable categorical agreement (CA ≥ 90%) and the rates of major error (ME <3%) and very major error (VME < 3%) of the two methods were compared with the reference method according to the criteria of ISO 20776-1. Fosfomycin resistance was detected in 15.8% of E. coli and 75% of Klebsiella spp. isolates using the reference method. Disk diffusion method showed CA 89.5%, ME 12.5% in E. coli isolates, and CA 75%, ME 100% in Klebsiella spp. isolates. No VME was detected in both methods. The rapid fosfomycin NP method resulted in CA 96.4%, ME 0.0%, VME 22.2% in E. coli isolates, and CA 77.3%, ME 81.8%, and VME 3% in Klebsiella spp. isolates. We believe the results from both of disk diffusion assay and rapid fosfomycin NP for the E. coli and Klebsiella spp. isolates are incompatible with the reference method and should not be used as an alternative to the agar dilution method.

Topics: Agar; Anti-Bacterial Agents; Diagnostic Tests, Routine; Drug Resistance, Bacterial; Escherichia coli; Escherichia coli Infections; Fosfomycin; Humans; Klebsiella; Klebsiella Infections; Klebsiella pneumoniae; Microbial Sensitivity Tests; Urinary Tract Infections

The aims of the study were to compare four different agar plate methods in the identification of carbapenemase-producing Klebsiella pneumoniae (CP-Kp) from rectal samples and to assess the role of phenotypic methodologies in the identification of carbapenemase type from clinical K. pneumoniae isolates. Two chromogenic agars (Brilliance CRE and CHROMagar KPC) were compared to MacConkey agar plates with ertapenem (ERT) or imipenem (IMP) disks for the identification of CP-Kp from 912 rectal swabs. CP-Kp was detected in 329 samples by either agar methodology (299 K. pneumoniae carbapenemase positive, 27 Verona integron-encoded metallo-β-lactamase positive and 3 K. pneumoniae carbapenemase and Verona integron-encodedmetallo-β-lactamase positive). Sensitivity of Brilliance CRE, CHROMagar KPC and MacConkey agar plus IMP or ERT disk (inhibition zone <25 mm) was 96.8, 99.2, 67.2 and 81.8 %, while specificity was 90.9, 78.2, 98.1 and 97.9 %, respectively. Synergy meropenem-disk tests with EDTA or phenylboronic acid were used in order to detect the carbapenemase type as compared to PCR results (blaVIM, blaKPC and blaNDM) from 2515 isolates with reduced susceptibility to any of the Etest-examined carbapenems (ERT, IMP or meropenem). Metallo-β-lactamase MP/MPI Etest was applied in 616 isolates. Sensitivity was 98.4, 90.9 and 82.2 % for phenylboronic acid synergy test, EDTA synergy test and metallo-β-lactamase Etest, respectively, while their specificity was high (>97.5 %). Phenotypic methodologies can provide reliable results for the identification of carbapenemase production among K. pneumoniae isolates. Chromogenic agars can be applied in high-risk patients as part of surveillance and infection control programs.

Topics: Agar; Bacterial Proteins; Bacteriological Techniques; beta-Lactamases; Culture Media; Humans; Klebsiella Infections; Klebsiella pneumoniae; Rectum; Sensitivity and Specificity

We studied the clinical and epidemiological characteristics of Klebsiella oxytoca-associated diarrhea in hospitalized patients in Hong Kong. Between 1 November 2009 and 30 April 2011, all inositol-fermenting colonies found on Simmons citrate agar supplemented with inositol, tryptophan, and bile salts (SCITB agar) used for the culturing of diarrheal stool samples were screened by a spot indole test for K. oxytoca. The overall sensitivity of SCITB agar plus the spot indole test (93.3%) for the detection of K. oxytoca in stool samples was superior to that of MacConkey agar (63.3%), while the specificities were 100% and 60.4%, respectively. The former achieved a 23-fold reduction in the workload and cost of subsequent standard biochemical identifications. Cytotoxin production and the clonality of K. oxytoca were determined by a cell culture cytotoxicity neutralization assay using HEp-2 cells and pulsed-field gel electrophoresis (PFGE), respectively. Of 5,581 stool samples from 3,537 patients, K. oxytoca was cultured from 117/5,581 (2.1%) stool samples from 104/3,537 (2.9%) patients. Seventy-six of 104 (73.1%) patients with K. oxytoca had no copathogens in their diarrheal stool samples. Twenty-four (31.6%) of 76 patients carried cytotoxin-producing strains, which were significantly associated with antibiotic therapy after hospital admission (50% versus 21.2%; P = 0.01). Health care-associated diarrhea was found in 44 (42%) of 104 patients with K. oxytoca, but there was no epidemiological linkage suggestive of a nosocomial outbreak, and PFGE showed a diverse pattern. None of the patients with cytotoxin-producing K. oxytoca developed antibiotic-associated hemorrhagic colitis, suggesting that K. oxytoca can cause a mild disease manifesting as uncomplicated antibiotic-associated diarrhea with winter seasonality.

Topics: Adolescent; Adult; Agar; Aged; Aged, 80 and over; Bacteriological Techniques; Bile Acids and Salts; Cell Line; Child; Child, Preschool; Citric Acid; Culture Media; Diarrhea; Electrophoresis, Gel, Pulsed-Field; Hepatocytes; Hong Kong; Hospitalization; Humans; Infant; Inositol; Klebsiella Infections; Klebsiella oxytoca; Male; Middle Aged; Molecular Typing; Sensitivity and Specificity; Tryptophan; Young Adult

Klebsiella pneumoniae carbapenemases (KPCs) have recently been described in Chicago, IL, especially among residents of long-term acute care hospitals (LTACHs). These patients are frequently transferred to local Chicago hospitals for higher acuity of medical care, and rapid detection and isolation of KPC-colonized LTACH residents may interrupt the introduction of KPCs into acute care hospitals. We evaluated the performance of a real-time PCR for bla(KPC) from enrichment broth versus direct plating of rectal surveillance swabs on two selective culture media, CHROMagar extended-spectrum-β-lactamase (ESBL) and vancomycin, amphotericin B, ceftazidime, and clindamycin (VACC) plates. Rectal surveillance swabs were collected as part of a point prevalence study of KPC carriage rates among 95 residents of two Chicago area LTACHs. Discrepant results between PCR and culture were resolved by subculturing the enrichment broth. Overall, 66 of 95 patients (69.5%) were colonized with KPCs, using the cumulative results of culture as a reference standard. Real-time PCR from enrichment broth was positive in 64 of 66 (97%) colonized patients, including nine surveillance swabs that were missed by both selective culture media. PCR demonstrated higher sensitivity, 97.0%, than culture using either CHROMagar or VACC plates (both with sensitivity of 77.3%). In addition, turnaround time was significantly shorter for the PCR-based method than for culture, with a mean of 24 h versus 64 to 72 h for CHROMagar and VACC plates (P < 0.0001). Overall, PCR for bla(KPC) represents the best screening test for KPCs with significantly higher sensitivity and with less hands-on time, resulting in a shorter time to results.

Topics: Agar; Bacterial Proteins; Bacteriological Techniques; beta-Lactamases; Chicago; Chromogenic Compounds; Culture Media; Hospitals; Humans; Klebsiella Infections; Klebsiella pneumoniae; Mass Screening; Real-Time Polymerase Chain Reaction; Rectum; Sensitivity and Specificity; Time Factors

MacConkey-inositol-carbenicillin agar has successfully been used as a primary selective medium for Klebsiella enumeration. With pure cultures, nearly 100% recovery of Klebsiella was observed by membrane filtration. With environmental samples using membrane filtration, 95% of typical pink- to red-colored colonies were verified as Klebsiella, as opposed to only 1% of yellow background colonies. Recovery of Klebsiella on MacConkey-inositol-carbenicillin agar was as good or better than on mEndo agar LES (Difco Laboratories). Recovery and percent colony confirmation with MacConkey-inositol-carbenicillin agar were greater than for other proposed Klebsiella selective media.

Topics: Agar; Carbenicillin; Fresh Water; Humans; Inositol; Klebsiella; Klebsiella Infections; Klebsiella pneumoniae; Sewage; Species Specificity; Water Microbiology

The biochemical characteristics of six strains of Klebsiella pneumoniae that produced H2S in TSI slants are described. All were biotypical except for the consistent characteristic of indole production. It is suggested that the qualities of H2S and indole production are linked biochemical features acquired by episomal transfer. The attention of bacteriology laboratory workers is directed to these strains, which are easily distinguished biochemically from other H2S-producing organisms by their otherwise biotypical pattern.

Topics: Agar; Animals; Biomarkers; Culture Media; Humans; Hydrogen Sulfide; Indoles; Iron; Klebsiella Infections; Klebsiella pneumoniae

In a series of 640 strains of Klebsiella isolated from clinical specimens over a 7-month period, there were sufficient biochemical differences between strains to allow a biochemical typing system to be established. Biochemical tests were done in solid media inoculated with a modified Steers inocula replicator. Biotypes were designated by a numerical coding system; 29 distinct biotypes were found among the 640 strains of Klebsiella. Serotyping of 270 of the strains was done by the Quellung reaction, and 40 capsular types were identified. Numerical biotypes and serotypes of strains appeared to vary independently. When used in conjunction, the two methods subdivided the strains into many more distinct types than either used alone. With the combined method over 100 types of Klebsiella were distinguished among the 270 isolates.

Topics: Agar; Bacteriological Techniques; Carbohydrate Metabolism; Evaluation Studies as Topic; Humans; Indoles; Klebsiella; Klebsiella Infections; Serotyping; Urease

Topics: Agar; Amino Sugars; Anti-Bacterial Agents; Biological Assay; Carbohydrate Metabolism; Chemical Precipitation; Chromatography, Paper; Chromatography, Thin Layer; Culture Media; Densitometry; Electrodes; Fermentation; Filtration; Freeze Drying; Genetic Variation; Genetics, Microbial; Glycosides; Hydrogen-Ion Concentration; Klebsiella Infections; Pigments, Biological; Species Specificity; Spores, Bacterial; Streptomyces; Ultraviolet Rays

Topics: Administration, Oral; Adolescent; Adult; Agar; Aged; Candidiasis; Cephalosporins; Escherichia coli; Escherichia coli Infections; Female; Haemophilus Infections; Haemophilus influenzae; Humans; Klebsiella; Klebsiella Infections; Male; Microbial Sensitivity Tests; Middle Aged; Nausea; Proteus; Proteus Infections; Staphylococcal Infections; Streptococcal Infections; Streptococcus; Streptococcus pneumoniae; Streptococcus pyogenes; Urinary Tract Infections; Vulvovaginitis

A 10-minute test, utilizing a urease paper-reagent strip (PATHO-TEC), for differentiating Klebsiella and Enterobacter species is described. By using a heavy suspension of organisms and 50 C temperature for incubation, 93% of Klebsiella strains (186/200) were positive and 95% of Enterobacter strains (190/200) were negative with this testing system. The rapid nature of the test (10 min), the facility with which it can be carried out, and the ease with which the strips can be stored and handled may make this a useful aid for the clinical microbiologist.

Topics: Agar; Bacteriological Techniques; Diagnosis, Differential; Enterobacter; Enterobacteriaceae Infections; Humans; Indicators and Reagents; Klebsiella; Klebsiella Infections; Paper; Urease