Transposon mutagenesis screen in Klebsiella pneumoniae identifies genetic determinants required for growth in human urine and serum.

Klebsiella pneumoniae is a global public health concern due to the rising myriad of hypervirulent and multidrug-resistant clones both alarmingly associated with high mortality. The molecular mechanisms underpinning these recalcitrant K. pneumoniae infection, and how virulence is coupled with the emergence of lineages resistant to nearly all present-day clinically important antimicrobials, are unclear. In this study, we performed a genome-wide screen in K. pneumoniae ECL8, a member of the endemic K2-ST375 pathotype most often reported in Asia, to define genes essential for growth in a nutrient-rich laboratory medium (Luria-Bertani [LB] medium), human urine, and serum. Through transposon directed insertion-site sequencing (TraDIS), a total of 427 genes were identified as essential for growth on LB agar, whereas transposon insertions in 11 and 144 genes decreased fitness for growth in either urine or serum, respectively. These studies not only provide further knowledge on the genetics of this pathogen but also provide a strong impetus for discovering new antimicrobial targets to improve current therapeutic options for K. pneumoniae infections.

Genomic Profile of a Multidrug-Resistant Klebsiella pneumoniae Strain Isolated from a Urine Specimen.

Klebsiella pneumoniae is an opportunistic pathogen mostly found in health care-associated infections but can also be associated with community-acquired infections and is in critical need of new antimicrobial agents for strains resistant to carbapenems. The prevalence of carbapenemase-encoding genes varies among studies. Multidrug-resistant K. pneumoniae strains can harbor several antimicrobial-resistant determinants and mobile genetic elements (MGEs), along with virulence genetic determinants in community settings. We aim to determine the genetic profile of a multidrug-resistant K. pneumoniae strain isolated from a patient with community-acquired UTI. We isolated a K. pneumoniae strain UABC-Str0120, from a urine sample of community-acquired urinary tract infection. Antimicrobial susceptibility tests and Whole-genome sequencing (WGS) were performed. The phylogenetic relationship was inferred by SNPs calling and filtering. UABC-Str0120 showed resistance toward ß-lactams, combinations with ß-lactamase inhibitors, and carbapenems. WGS revealed the presence of genes conferring resistance to aminoglycosides, ß-lactams, carbapenems, quinolones, sulfonamides, phosphonates, phenicols, and quaternary ammonium compounds, 77 subsystems of virulence genes were identified, and an uncommon sequence type ST5889 was also determined. The sequenced strain harbors several MGEs. The UABC-Str0120 recovered from a urine sample harbors several virulence and antimicrobial resistance determinants, which assembles an endangering combination for an immunocompromised or a seemly healthy host, given its presence in a community setting.

Emergence of polymyxin B-heteroresistant hypervirulent Klebsiella pneumoniae from an individual in the community with asymptomatic bacteriuria.

BACKGROUND: The heteroresistance of polymyxin B, a last-resort antibiotic used to treat many serious bacterial infections, may lead to antibiotic treatment failure. However, polymyxin B-heteroresistant isolates are rare in individuals living in the community. We report a polymyxin B-heteroresistant hypervirulent Klebsiella pneumoniae (hvKP) isolate from an individual in the community with asymptomatic bacteriuria. RESULTS: The NYTJ35 isolate had multiple virulence genes that encoded a mucoid phenotype regulator (rmpA), aerobactin (iucABCD-iutA), salmochelin (iroBCDN), yersiniabactin (irp1-2 and ybtAEPQSTUX), and a truncated rmpA2. Infection of galleria mellonella larvae indicated the isolate was hypervirulent. Antimicrobial susceptibility testing showed it was susceptible to all tested antibiotics except polymyxin B. The proportion of surviving bacteria was 1.2 × 10- 7 based on the population analysis profile (PAP) method, suggesting the presence of polymyxin B heteroresistance. The isolate was not hypermucoviscous, but it was a strong biofilm producer. It had capsular serotype K1 and belonged to sequence type 23 (ST23). The isolate also had the D150G substitution in phoQ, which is known to confer polymyxin B resistance. CONCLUSIONS: We identified the co-occurrence of hypervirulence and polymyxin B heteroresistance in a K. pneumoniae isolate from an individual with asymptomatic bacteriuria. We suggest the use of increased screening for hvKP in individuals living in the community.

Distribution, characterization, and antibiotic resistance of hypervirulent Klebsiella pneumoniae isolates in a Chinese population with asymptomatic bacteriuria.

BACKGROUND: Asymptomatic bacteriuria (ASB) frequently occurs among all ages and may develop into urinary tract infections (UTIs). Hypervirulent Klebsiella pneumoniae (hvKP) has become a new threat to human health. In our study, we aimed to investigate the epidemiological characteristics of hvKP in population with ASB. RESULTS: A total of 61 K. pneumoniae isolates were collected from 7530 urine samples between October and December 2020. The strains were sensitive to most of the antimicrobial agents tested, but a polymyxin resistant strain was found (MIC>16 µg/mL). Three serotypes were detected, including K1 (16.4%, 10/61), K5 (1.6%, 1/61) and K57 (3.2%, 2/61). Four strains (KPNY9, KPNY31, KPNY40, and KPNY42) carried a combination of two or more hypervirulent markers (peg-344, iroB, iucA, prmpA, and prmpA2), and their survival rates after Galleria mellonella infection were lower than those of the other strains (40.0 vs. 70.0%), suggesting that they were hvKP. These hvKP strains with lower biofilm forming ability than classical K. pneumoniae (0.2625 ± 0.0579 vs. 0.6686 ± 0.0661, P = 0.033) were identified as belonging to K2-ST65, K2-ST86, K57-ST592, and K2-ST5559 (a new ST type). KPNY31 (ST5559) shared a close genetic relationship with KPNY42 (ST86) and other ST86 isolates, which have been detected in both nosocomial and community-acquired infections. CONCLUSIONS: The hvKP with relatively weak biofilm formation was detected in a population with ASB, which was more likely to cause bacteremia and serious consequences. A novel sequence type (ST5559) hvKP derived from ST86 was found. Therefore, hvKP should be monitored in the population with ASB.

Diffusion of OXA-48 carbapenemase among urinary isolates of Klebsiella pneumoniae in non-hospitalized elderly patients.

BACKGROUND: Recently, a dramatic increase of Klebsiella pneumoniae positive for OXA-48 ß-lactamases was observed first in the hospital setting and later in the long-term care facilities (LTCFs) and community in the Zagreb County, particularly, in urinary isolates. The aim of the study was to analyse the epidemiology and the mechanisms of antibiotic resistance of OXA-48 carbapenemase producing K. pneumoniae strains isolated from urine of non-hospitalized elderly patients. RESULTS: The isolates were classified into two groups: one originated from the LTCFs and the other from the community. Extended-spectrum ß-lactamases (ESBLs) were detected by double disk-synergy (DDST) and combined disk tests in 55% of the isolates (51/92). The ESBL-positive isolates exhibited resistance to expanded-spectrum cephalosporins (ESC) and in majority of cases to gentamicin. LTCFs isolates showed a significantly lower rate of additional ESBLs and consequential resistance to ESC and a lower gentamicin resistance rate compared to the community isolates, similarly to hospital isolates in Zagreb, pointing out to the possible transmission from hospitals.ESBL production was associated with group 1 of CTX-M or SHV-12 ß-lactamases. Ertapenem resistance was transferable from only 12 isolates. blaOXA-48 genes were carried by IncL plasmid in 42 isolates. In addition IncFII and IncFIB were identified in 18 and 2 isolates, respectively. Two new sequence types were reported: ST4870 and ST4781. CONCLUSIONS: This study showed eruptive and extensive diffusion of OXA-48 carbapenemase to LTCFs and community population in Zagreb County, particularly affecting patients with UTIs and urinary catheters. On the basis of susceptibility testing, ß-lactamase production, conjugation experiments, MLST and plasmid characterization it can be concluded that there was horizontal gene transfer between unrelated isolates, responsible for epidemic spread of OXA-48 carbapenemase in the LTCFs and the community The rapid spread of OXA-48 producing K. pneumoniae points out to the shortcomings in the infection control measures.

Changes of urine isolates of Escherichia coli and Klebsiella pneumoniae biofilm affect monocytes' response.

The Gram negative rods as Escherichia coli and Klebsiella pneumoniae belong to the most common etiology agents of urinary tract infections. The aim of our study was to assess the diversity of biofilm formed in different urinary tract diseases and their impact on monocytes' adherence and activation. The bacteria were obtained from patients with different kidney problems. Some of the patients were after renal transplantation, some of them were not. Changes in the size and granularity of monocytes, as well as their adherence to biofilm, were assessed using FACSVerse flow cytometer after 1 h co-incubation of monocytes and bacterial biofilm in 37 °C. The obtained results were validated against monocytes incubated without bacteria. The isolates from patients with chronic kidney disease formed the most adherent biofilm regardless the presence or absence of inflammatory reaction. Adherence of monocytes also increased during therapy with immunosuppressive agents, but monocytes' response was different when cyclosporine or tacrolimus were used. Additionally the presence of inflammatory reaction in patients with kidney disease modified the monocytes response when the immunosuppressive drugs were used. Considering the obtained results, we conclude that the changes of monocytes' morphology in response to biofilm formed by Gram negative rods could become a tool to detect urinary tract infection, especially in those groups of patients, where the knowledge of ongoing inflammation is important and the standard tools fail to detect it.

Antimicrobial resistance comparison of Klebsiella pneumoniae pathogens isolated from intra-abdominal and urinary tract infections in different organs, hospital departments and regions of China between 2014 and 2017.

BACKGROUND: We describe antibiotic resistance trends of Klebsiella pneumoniae pathogens, responsible for urinary tract infections (UTIs) and intra-abdominal infections (IAIs), isolated from different organs and tissues, hospital departments and Chinese regions between 2014 and 2017. METHODS: Resistances of UTIs and IAIs derived K. pneumoniae isolates from 17 hospitals in 7 Chinese regions to amikacin, imipenem, piperacillin-tazobactam, ertapenem, and cefepime were unequivocally established. RESULTS: Overall resistance rates of K. pneumoniae IAI isolates obtained from gallbladder and abscesses increased to amikacin (14.29-30.95%) and for liver, gallbladder, and abscesses to imipenem (14.29-38.10%), piperacillin-tazobactam (23.81-38.10%), and ertapenem (23.81-38.10%) in 2017, but were constant (20-30%) for K. pneumoniae isolates from UTIs from 2014 to 2017. In medical and surgical ICUs, resistance rates to all tested antibiotics rose to ∼60% for IAIs, which was also reflected in higher resistance rates of hospital acquired (HA) compared to community acquired (CA) infections. In medical ICUs resistance rates increased to 50-60% for amikacin, imipenem, and ertapenem for UTI-derived K. pneumoniae isolates in 2017. Resistance rates to all tested antibiotics were highest in the east Jiangzhe region of China, being ∼60% for K. pneumoniae isolates from IAIs and 40% for K. pneumoniae isolates from UTIs to ertapenem and imipenem, as well as > 40% for piperacillin-tazobactam in 2017. CONCLUSION: In China, ICUs resistance rates to K. pneumoniae IAIs and UTIs isolates was increased in 2017 for all tested antimicrobials including carbapenems, which makes them no longer suitable for empiric treatment. In the east Jiangzhe region this was a general trend that was independent of the type of hospital department.

Successful Treatment of Pandrug-resistant Klebsiella pneumoniae Infection With Ceftazidime-avibactam in a Preterm Infant: A Case Report.

Pandrug-resistant (PDR) bacterial infections in intensive care units are emerging as a severe problem. Therefore, new antibiotic options are urgently needed for the treatment of PDR infections in pediatric age groups, especially neonates. Herein, we report a 25 days old preterm neonate successfully treated with ceftazidime-avibactam due to a urinary tract infection caused by PDR Klebsiella pneumoniae. We aimed to describe our experiences about the safety and efficacy of ceftazidime-avibactam treatment.

Co-occurrence of a novel VIM-1 and FosA3-encoding multidrug-resistant plasmid and a KPC-2-encoding pKP048-like plasmid in a clinical isolate of Klebsiella pneumoniae sequence type 11.

The spread of carbapenem-resistant Enterobacteriaceae (CRE) worldwide remains a major threat to public health. Notably, carbapenemase-encoding genes are usually located in plasmids harboring other resistance determinants, and isolates having multiple plasmids are often highly resistant to carbapenems. In this study, we characterized the genetic context of coproduction of KPC-2, VIM-1, and FosA3 via two plasmids in the multidrug-resistant Klebsiella pneumoniae sequence type 11 (ST11) isolate JS187, recovered during an outbreak of KPC-2-producing K. pneumoniae in a Chinese teaching hospital in 2008. Plasmid p187-1, coharboring blaVIM-1 and fosA3, consisted of a pKOX-R1-like backbone and two multidrug resistant (MDR) regions separated by pKHS1-like backbone sequences involving plasmid replication and stability. The MDR region 1 was a chimera composed of the blaVIM-1-bearing In916-like integron and Tn1721-like transposon, and was disrupted by sequential insertion of an IS26-based transposition unit carrying blaCTX-M-3 and a ΔTn3-like transposon bearing blaTEM-1. MDR region 2 was an IS26-array structure with fosA3 and blaSHV-12. Plasmid p187-2 harboring blaKPC-2 was closely related to pKP048. blaKPC-2 in p187-2 was carried by a Tn1721 variant, which differed from the prototype Tn1721-blaKPC-2 transposon observed in pKP048 by disruption of an IS26 at Tn3 and deletion of a 31-kb MDR fragment. Co-existence of the novel VIM-1- and FosA3-encoding MDR plasmid p187-1 and the KPC-2-encoding pKP048-like plasmid p187-2 made K. pneumoniae JS187 highly resistant to carbapenems. Moreover, p187-1 still carried genes conferring resistance to cephalosporins, fosfomycin, chloramphenicol, and quaternary ammonium, posing substantial challenges for the treatment of Enterobacteriaceae infections. Thus, monitoring the prevalence and evolution of these plasmids and/or strains is critical.

Efflux pump activity, biofilm formation and antibiotic resistance profile of Klebsiella spp. isolated from clinical samples at Lagos University Teaching Hospital.

OBJECTIVE: Nosocomial and community acquired multidrug resistant Klebsiella infections are wide spread resulting in high morbidity and mortality due to limited number of antibiotics treatment options. This study investigated efflux pump activity, biofilm forming potential and antibiotic susceptibility profile of Klebsiella spp. isolated from clinical samples in a tertiary hospital in Lagos Nigeria. Eighteen clinical Klebsiella spp. isolated from urine, blood and sputum were subjected to antibiotic susceptibility testing using the disc diffusion method. Efflux pump activity was evaluated by the ethidium bromide cartwheel method and biofilm forming ability was determined by the tissue culture plate technique. RESULTS: All 18 (100%) Klebsiella isolates were resistant to cefuroxime, cefixime, amoxicillin - clavulanate, ampicillin + cloxacillin, cefotaxime, and imipenem. Seventeen (94.4%) were resistant to ofloxacin while sixteen (88.9%) were resistance to nalidixic acid, Gentamicin and levofloxacin. All Klebsiella isolates possessed active efflux pump with the ability to form biofilm. However, their biofilm forming capabilities varied as 4 (22.2%) were strong, 3 (16.7%) were moderate and 11 (61.1%) were weak biofilm formers. Findings in this study reveal multiple factors at play in mediating the high level of antibiotic resistance observed in Klebsiella isolates. Hence a multifaceted approach is advocated in managing the infections caused by the pathogen.

Adaptive evolution of virulence and persistence in carbapenem-resistant Klebsiella pneumoniae.

Among the most urgent public health threats is the worldwide emergence of carbapenem-resistant Enterobacteriaceae1-4, which are resistant to the antibiotic class of 'last resort'. In the United States and Europe, carbapenem-resistant strains of the Klebsiella pneumoniae ST258 (ref. 5) sequence type are dominant, endemic6-8 and associated with high mortality6,9,10. We report the global evolution of pathogenicity in carbapenem-resistant K. pneumoniae, resulting in the repeated convergence of virulence and carbapenem resistance in the United States and Europe, dating back to as early as 2009. We demonstrate that K. pneumoniae can enhance its pathogenicity by adopting two opposing infection programs through easily acquired gain- and loss-of-function mutations. Single-nucleotide polymorphisms in the capsule biosynthesis gene wzc lead to hypercapsule production, which confers phagocytosis resistance, enhanced dissemination and increased mortality in animal models. In contrast, mutations disrupting capsule biosynthesis genes impair capsule production, which enhances epithelial cell invasion, in vitro biofilm formation and persistence in urinary tract infections. These two types of capsule mutants have emerged repeatedly and independently in Europe and the United States, with hypercapsule mutants associated with bloodstream infections and capsule-deficient mutants associated with urinary tract infections. In the latter case, drug-tolerant K. pneumoniae can persist to yield potentially untreatable, persistent infection.

Elevated urinary IL-1ß levels in multidrug resistant Escherichia coli and Klebsiella infections.

INTRODUCTION: Multidrug resistant (MDR) E. coli and Klebsiella infections are rising. IL-1ß has been implicated in the differentiation of symptomatic and asymptomatic urinary tract infections, but its role in MDR infections has not been elucidated. MATERIAL AND METHODS: Urinary IL-1ß levels were analysed by ELISA. RESULTS: Urinary IL-1ß levels were statistically higher in patients with bacterial burden compared to controls and also in patients with MDR bacterial infections compared to those with multidrug-sensitive bacterial infections. CONCLUSIONS: Urinary IL-1ß levels might be a useful tool to identify patients with challenging MDR bacterial infections.

Positive Culture Samples of Infants with Neonatal Infections in a Tertiary Neonatal Center in Isfahan, Iran.

BACKGROUND: The prevalence of microorganisms in the neonatal intensive care unit (NICU) and neonatal internal wards is constantly changing, thus rendering the practice of empiric antibiotic therapy ineffective due to the resistance of these microorganisms. Therefore, the purpose of this study was to determine the relative frequency of positive cultures of Bactec, blood, cerebrospinal fluid (CSF) and urine in infants admitted to the NICU and neonatal internal ward in Al-Zahra hospital in 2011-2017. METHODS: In this cross-sectional descriptive study, we evaluated 466 positive culture samples from 2853 different cultures (blood, urine, CSF, etc) from infants admitted to the NICU and neonatal internal ward with clinical signs of neonatal infection in Al-Zahra hospital. Isfahan in 2011-2017. The samples were evaluated for type of microorganisms and sensitivity to antibiotics. RESULTS: Positive cultures among Bactec, blood, CSF and urine culture samples were reported at 15.5% (95% confidence interval [CI]: 12.8-18.1) 9.3% (95% CI: 6.8-11.7), 6.4% (95% CI: 4.3-8) and 28.6% (95% CI: 25.4-31.7), respectively. Staphylococcus epidermidis was the most common species in Bactec (46.7%; 95% CI: 38.7-54.6), blood (53.1%; 95% CI: 39.1-67), and CSF (37.1%; 95% CI: 21-53.1) cultures while Klebsiella pneumoniae was the most frequent species in urine culture (28%; 95% CI: 22.2-33.7). CONCLUSION: Considering the results of Bactec and blood cultures, it is essential to reduce staphylococcal infections in our settings.

Biofilm formation by ESBL-producing strains of Escherichia coli and Klebsiella pneumoniae.

OBJECTIVES: Biofilm production in extended spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae provides a favourable environment for the exchange of antibiotic-resistance genes and could facilitate widespread dissemination. We aimed to assess biofilm development in ESBL-producing E. coli and K. pneumoniae isolates and determine how development relates to microbiological characteristics and clinical outcomes. METHODS: 147 ESBL-producing E. coli and 82 K. pneumoniae were genetically characterized. Biofilm formation was measured at 1.5, 4, 6, and 24 h during culture in blood heart infusion using a microbead immobilization assay (BioFilm Ring test®). Results were given as biofilm formation index (BFI) with lower values indicating increased presence of biofilm (range = 0-21). RESULTS: In total, 57.1% of strains were strong producers of biofilm (BFI < 2), whereas 13.4% lacked biofilm production (BFI > 18). Standard biofilm production (BFI < 7) was common in E. coli isolates (61.9%). For E. coli, biofilm production was less frequently observed in ST131 clones (p = 0.03) but more frequently in strains harbouring toxin (p = 0.008) or adhesin (p = 0.008) virulence factor genes. Despite almost all K. pneumoniae having standard biofilm production (90.2%), there was a 2.4-times higher odds of observing biofilm in ST29/147/323 versus other ST-types (p = 0.13). Patients with standard biofilm producing isolates were not at increased risk of transfer to intensive-care (odds-ratio=2.80, 95%CI=0.59-13.21) or death within 12-months (odds-ratio=1.61, 95%CI=0.75-3.43). CONCLUSION: In these ESBL-producing strains, biofilm production is linked to certain virulence factors in E. coli and is common in K. pneumoniae. Further exploration of whether biofilm production increases dissemination and risk of severe clinical outcomes is needed in larger collections of isolates.

Clozapine-induced bicytopenia: An unusual side effect.

Agranulocytosis is a rare documented side effect of clozapine which can be associated with grave consequences. When it is associated with other blood dyscrasia, prognosis worsens further. In literature, there are very few cases of pancytopenia and bicytopenia caused by clozapine. We present a case of bicytopenia (reduced white and red blood cells' counts) caused by clozapine within a month of therapy and complicated by a Klebsiella pneumoniae infection. Patient improved in 3 weeks after stopping clozapine along with medical management in the Intensive Care Unit. Such side effects, though rare, can be life threatening and warrants intermittent complete blood monitoring besides regular assessment of granulocytes and neutrophils when any patient is prescribed clozapine.

Determination of gyrA and parC mutations and prevalence of plasmid-mediated quinolone resistance genes in Escherichia coli and Klebsiella pneumoniae isolated from patients with urinary tract infection in Iran.

OBJECTIVES: Fluoroquinolones (FQs) are recommended as the drugs of choice for the empirical treatment of urinary tract infections (UTIs). This study investigated the molecular determinants of FQ resistance in Escherichia coli and Klebsiella pneumoniae isolates in Iran. METHODS: A total of 364 clinical isolates of E. coli (n=144) and K. pneumoniae (n=220) were collected from patients with UTI. Susceptibility of the isolates to ciprofloxacin, levofloxacin, gatifloxacin and nalidixic acid was evaluated by disk diffusion. The presence of qnrA, qnrB and qnrS genes was assessed by PCR. Nucleotide sequences of the gyrA and parC genes were determined. RESULTS: Eighty-seven (60.4%) and 15 (6.8%) E. coli and K. pneumoniae isolates, respectively, were resistant to at least one of the tested FQs. Plasmid-mediated quinolone resistance (PMQR) genes were detected in 12.6% and 60.0% of FQ-resistant E. coli and K. pneumoniae, respectively. Whilst qnrB predominated in K. pneumoniae, qnrS was the most prevalent PMQR gene in E. coli. S83L (98.9%) and D87N (59.8%) were the most frequent mutations identified in GyrA of E. coli, and 55.2% (n=48) of FQ-resistant E. coli isolates had mutation in ParC harbouring S80I and E84V substitutions. The GyrAS83L substitution was found in only one FQ-resistant K. pneumoniae isolate. CONCLUSIONS: FQ resistance was much more common in E. coli isolates than in K. pneumoniae. Whilst mutations in the drug target-encoding genes gyrA and parC were the major mechanisms involved in FQ resistance in E. coli, PMQR determinants commonly mediated FQ resistance in K. pneumoniae.

Emergence of ArmA, a 16S rRNA methylase in highly aminoglycoside-resistant clinical isolates of Klebsiella pneumoniae and Klebsiella oxytoca in Okinawa, Japan.

This study describes highly aminoglycoside-resistant Klebsiella pneumoniae and Klebsiella oxytoca clinical isolates obtained from an inpatient in Okinawa, Japan, with no known record of traveling overseas. The minimum inhibitory concentrations of amikacin and arbekacin against these strains were >1024 µg/ml. Whole-genome sequencing analysis revealed that these isolates harbored armA, which encodes a 16S rRNA methylase, ArmA, that confers pan-aminoglycoside resistance. This is the second report of K. pneumoniae harboring armA and the first report of K. oxytoca harboring a 16S rRNA methylase encoding gene in Japan.

Antimicrobial resistance profiles and genotypes of extended-spectrum ß-lactamase- and AmpC ß-lactamase-producing Klebsiella pneumoniae isolated from dogs in Beijing, China.

OBJECTIVES: Klebsiella pneumoniae, which exists in the intestinal and respiratory tracts of humans and animals, is an important conditional pathogen in many animals. The aim of the current study was to investigate the antimicrobial resistance profiles and genotypes of extended-spectrum ß-lactamase (ESBL)- and AmpC ß-lactamase-producing K. pneumoniae isolated from dogs. METHODS: A total of 285 isolates, collected from faecal and urine samples of diseased dogs in a Veterinary Teaching Hospital in Beijing, were characterised by antimicrobial susceptibility testing and screened for ESBL and AmpC ß-lactamase phenotypes. The relevant genes were identified by polymerase chain reaction and sequencing. RESULTS: All K. pneumoniae isolates were susceptible to meropenem, while the rates of resistance to the remaining 27 tested antimicrobials ranged from 24% to 97%. A total of 53% and 18% of K. pneumoniae isolates were positive for ESBL and AmpC ß-lactamase production, respectively. ESBL/AmpC-producing strains were significantly resistant to more antimicrobial agents compared non-ESBL/AmpC-producing strains (P<0.05). CTX-M groups 1 and 9, and DHA-1 were the predominant genotypes of the ESBL/AmpC-producing K. pneumoniae isolates. CONCLUSIONS: In conclusion, the high percentage of drug resistance among K. pneumoniae isolates suggests that routine detection of ESBL production by reliable laboratory methods is required in small animal clinical practice.

[Purple urine bag syndrome: An uncommon manifestation of urinary tract infection]. / Síndrome de la bolsa de orina morada (SBOM): una manifestación infrecuente de infección de vías urinarias (IVU).

CASE REPORT: A 57-year-old paraplegic male diagnosed with non-Hodgkin's lymphoma and complete spinal cord compression arrived at our clinic because of fever and purple discoloration of the urine. We diagnosed purple urine bag syndrome (PUBS) and treated him with oral ciprofloxacin and urinary catheter replacement. DISCUSSION: PUBS is an unusual phenomenon that occurs predominantly in bedridden patients with long-term urinary catheters, presenting as a purple discoloration of the urine bag. Its pathogenesis involves the metabolism of indoxyl sulfate by sulfatase-producing bacteria. Knowledge of this entity is important in order to avoid unnecessary diagnostic workup and treatment.