Clinical and microbiological characteristics of Klebsiella pneumoniae from community-acquired recurrent urinary tract infections

Influence of preoperative urine culture and bacterial species on urogenital sepsis after ureteral flexible lithotripsy in patients with upper urinary tract stones

Objective

This retrospective study aims to identify risk factors for urogenic sepsis in patients with upper urinary tract stones following ureteral flexible lithotripsy (FURL). Additionally, we analyze the clinical characteristics of bacterial infections post-surgery.

Methods

A total of 759 patients who underwent FURL at the Urology Department of Zunyi Medical University were included. Univariate and multivariate Logistic regression analyses were conducted to identify independent risk factors for urogenic sepsis post-FURL. The distribution of bacteria based on preoperative urine cultures was also analyzed. Statistical analysis was performed using R4.2.2 software.

Results

Of the 759 patients, positive preoperative urine culture, urine nitrite positivity, urine white blood cell count (WBC) ≥ 200 cells/μL, residual stones, and neutrophil-to-lymphocyte ratio (NLR) were found to be independent risk factors for urogenic sepsis after FURL. Among the 164 patients with positive preoperative urine cultures, 32 developed urogenic sepsis post-surgery, with 68.75% having positive preoperative cultures. The leading pathogens causing postoperative urogenic sepsis were Escherichia coli (E. coli), Enterococcus faecium, Proteus mirabilis, and Klebsiella pneumoniae. The probabilities of progression to urogenic sepsis were as follows: E. coli 19% (n = 12), Enterococcus faecium 43% (n = 3), Proteus mirabilis 33.3% (n = 1), and Klebsiella pneumoniae 33.3% (n = 1). The ages of affected patients were 47.17 ± 13.2, 53.7, 41, and 79 years, respectively. Rates of comorbid diabetes were 36.4, 66.7, 50, 100%, with nitrite positivity rates at 72.7, 33.3, 50, 0%. Ten female patients were infected with E. coli, while patients infected with Klebsiella pneumoniae had an NLR of 7.62.

Conclusion

Positive preoperative urine culture, urine nitrite positivity, urine WBC ≥ 200 cells/μL, residual stones, and NLR are independent risk factors for urogenic sepsis after FURL. Escherichia coli is the predominant pathogen post-FURL, with notable female prevalence and nitrite-positive urine in infections. Enterococcus faecium infections are associated with diabetes.

Clinical and microbiological characteristics of female patients with acute pyelonephritis who experienced urinary tract infections within the previous year

BACKGROUND

This study aimed to examine the clinical and microbiological characteristics of female patients with recurrent acute pyelonephritis (APN).

METHODS

A retrospective cohort study was conducted at a tertiary care hospital in South Korea from July 2019 to December 2021. All female patients aged ≥ 19 years who were diagnosed with community-acquired APN on admission were enrolled. The recurrent group included patients with APN who experienced urinary tract infections within the previous year. The clinical characteristics, types of causative organisms, major antibiotic resistance, and molecular characteristics of Escherichia coli strains were compared between the recurrent and non-recurrent groups.

RESULTS

A total of 285 patients with APN were analyzed, including 41 (14.4%) in the recurrent group. Compared to the non-recurrent group, the recurrent group had a higher Charlson Comorbidity Index (1.8 ± 2.1 vs. 1.1 ± 1.5; P = 0.01) and a higher proportion of bladder abnormalities, such as neurogenic bladder (12.2% vs. 2.0%; P = 0.001) and urinary catheterization (12.2% vs. 1.6%; P < 0.001). Escherichia coli was the most common causative organism in both groups. The proportion of Klebsiella pneumoniae (17.1% vs. 4.7%; P = 0.007) and Pseudomonas aeruginosa (5.7% vs. 0.5%; P = 0.014) as a causative organism was higher in the recurrent group. Regarding the microbiological characteristics of Escherichia coli, there were no significant differences in the proportion of antibiotic resistance, phylogenetic groups, resistance genes, and virulence factors between the two groups. Multivariable analysis showed that neurogenic bladder and a history of admission or antibiotic use during 1 year prior to inclusion were significantly associated with recurrent APN.

CONCLUSIONS

The proportion of causative organisms except Escherichia coli was higher in the recurrent group than in the non-recurrent group. Neurogenic bladder and a history of admission or antibiotic use during 1 year prior to inclusion were risk factors for recurrent APN.

Pathogen species are the risk factors for postoperative infection of patients with transurethral resection of the prostate: a retrospective study

This study aimed to analyze the infection risk factors for transurethral resection of the prostate (TURP) and establish predictive models to help make personalized treatment plans. Our study was designed one-center and retrospectively enrolled 1169 benign prostatic hyperplasia (BPH) patients. Risk factors were explored for postoperative infection. A TURP-postoperative infection (TURP-PI) model with infection prediction values was created. The improved-TURP-PI (I-TURP-PI) model, including extra new factors (pathogens species), was also built to see whether it could optimize the prediction abilities. At last, we developed a nomogram for better clinical application. Operation time, preoperative indwelling urinary catheter (PIUC), and positive preoperative urine culture were independent risk factors (all P < 0.05). Interestingly, pathogens species in pre-surgery urine (PEnterococcus faecium = 0.014, PPseudomonas aeruginosa = 0.086) were also independent risk factors. Patients with positive Enterococcus faecium (37.50%) were most likely to have postoperative infection. We built two models with AUCTURP-PI = 0.709 (95% CI 0.656-0.763) and AUCI-TURP-PI = 0.705 (95% CI 0.650-0.760). The nomogram could help improve the prediction ability. To our knowledge, our study is the first to use pathogen species in urine before surgery as risk factors for infection prediction after TURP. TURP-PI and I-TURP-PI models have essential roles in predicting patients' postoperative infections and in better postoperative antibiotic decision-making.

Epidemiology of extended-spectrum β-lactamases in Enterobacterales in Taiwan for over two decades

The emergence of antimicrobial resistance among microorganisms is a serious public health concern, and extended-spectrum β-lactamases (ESBL)-producing Enterobacterales is one of the major concerns among antibiotic-resistant bacteria. Although the prevalence of ESBL in Enterobacterales has been increasing with time, the prevalence of ESBL could differ according to the species, hospital allocation, sources of infections, nosocomial or community acquisitions, and geographic regions. Therefore, we conducted a comprehensive review of the epidemiology of ESBL-producing Enterobacterales in Taiwan. Overall, the rates of ESBL producers are higher in northern regions than in other parts of Taiwan. In addition, the genotypes of ESBL vary according to different Enterobacterales. SHV-type ESBLs (SHV-5 and SHV-12) were the major types of Enterobacter cloacae complex, but Serratia marcescens, Proteus mirabilis, Escherichia coli, and Klebsiella pneumoniae were more likely to possess CTX-M-type ESBLs (CTX-M-3 and CTX-M-14). Moreover, a clonal sequence type of O25b-ST131 has been emerging among urinary or bloodstream E. coli isolates in the community in Taiwan, and this clone was potentially associated with virulence, ESBL (CTX-M-15) production, ciprofloxacin resistance, and mortality. Finally, the evolution of the genetic traits of the ESBL-producing Enterobacterales isolates helps us confirm the interhospital and intrahospital clonal dissemination in several regions of Taiwan. In conclusion, continuous surveillance in the investigation of ESBL production among Enterobacterales is needed to establish its long-term epidemiology.

Healthcare Facilities as Potential Reservoirs of Antimicrobial Resistant Klebsiella pneumoniae: An Emerging Concern to Public Health in Bangladesh

The emergence of virulent extended spectrum β-lactamase producing Klebsiella pneumoniae (ESBL-KP) including carbapenem-resistant Klebsiella pneumoniae (CRKP) in hospital-acquired infections has resulted in significant morbidity and mortality worldwide. We investigated the antibiotic resistance and virulence factors associated with ESBL-KP and CRKP in tertiary care hospitals in Bangladesh and explored their ability to form biofilm. A total of 67 ESBL-KP were isolated from 285 Klebsiella pneumoniae isolates from environmental and patient samples from January 2019 to April 2019. For ESBL-KP isolates, molecular typing was carried out using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR), antibiotic susceptibility testing, PCR for virulence and drug-resistant genes, and biofilm assays were also performed. All 67 isolates were multidrug-resistant (MDR) to different antibiotics at high levels and 42 isolates were also carbapenem-resistant. The most common β-lactam resistance gene was bla_CTX-M-1 (91%), followed by bla_TEM (76.1%), bla_SHV (68.7%), bla_OXA-1 (29.9%), bla_GES (14.9%), bla_CTX-M-9 (11.9%), and bla_CTX-M-2 (4.5%). The carbapenemase genes bla_KPC (55.2%), bla_IMP (28.4%), bla_VIM (14.9%), bla_NDM-1 (13.4%), and bla_OXA-48 (10.4%) and virulence-associated genes such as fimH (71.6%), ugeF (58.2%), wabG (56.7%), ureA (47.8%) and kfuBC (28.4%) were also detected. About 96.2% of the environmental and 100% of the patient isolates were able to form biofilms. ERIC-PCR-based genotyping and hierarchical clustering of K. pneumoniae isolates revealed an association between environmental and patient samples, indicating clonal association with possible transmission of antimicrobial resistance genes. Our findings can help in improving patient care and infection control, and the development of public health policies related to hospital-acquired infections.

The effect of preoperative urine culture and bacterial species on infection after percutaneous nephrolithotomy for patients with upper urinary tract stones

To study the relationship between preoperative urine culture, bacterial species and infection after percutaneous nephrolithotomy in patients with upper urinary tract stones, and summarize the clinical characteristics of different bacterial infections. From January 2014 and January 2020, 963 patients with upper urinary tract stones who underwent PCNL in the department of urology of Fujian provincial hospital were included in the study. Information included the patient’s age, gender, weight, diabetes, chronic disease history, urine routine, preoperative urine culture results, stone size, number of stones, hydronephrosis level, operation time, body temperature, heart rate, blood pressure, breathing rate, hemoglobin, serum creatinine, bilirubin, platelets and whether there was preoperative infection were recorded. 141 patients (14.6%) had a positive urine culture before surgery, and 7 of them had multiple bacterial infections. The most common pathogenic bacteria was Escherichia coli, followed by Enterococcus and Klebsiella pneumoniae. A total of 74 cases (7.7%) of 963 patients with infection after PCNL occurred, 24 cases (32.4%) of infected patients progressed to urinary septic shock. Univariate analysis shown that the probability of infection in patients with long operation time and positive urine culture was significantly higher, and the difference was statistically significant. Further multivariate logistic regression analysis shown that positive urine culture before operation and long operation time were independent risk factors for infection after PCNL. Among the 29 patients with septic shock, 18 cases (62.1%) had a positive urine culture before surgery. The incidence (43.9%) of postoperative infection in Escherichia coli positive patients was significantly higher than that in the negative group, and the difference was statistically significant. The rate of patients with Escherichia coli infection progressing to septic shock was 9 cases (60%). 2 patients with Enterococcus faecium infection and 2 patients with Klebsiella pneumoniae infection all progressed to septic shock. The age of patients with post-PCNL infection caused by Escherichia Coli, Enterococcus faecium and Klebsiella pneumoniae were 58.53 ± 11.73 years, 76.5 years and 74 years.The body temperature of patients with post-PCNL infection caused by Escherichia Coli, Enterococcus faecium and Klebsiella pneumoniae were 39.10 ± 0.25 °C, 39.45 °C and 38.65 °C. The highest pct value of patients with post-PCNL infection caused by Escherichia Coli, Enterococcus faecium and Klebsiella pneumoniae were 80.62 ± 31.45 ng/mL, 24.32 ng/mL and 8.45 ng/mL. The nitrite positive rate of patients with post-PCNL infection caused by Escherichia Coli, Enterococcus faecium and Klebsiella pneumoniae were 64.51%, 16.6% and 0. Postoperative infection of PCNL is significantly correlated with positive preoperative urine culture, and positive preoperative urine culture is an independent risk factor for postoperative infection. The most common pathogen of postoperative infection of PCNL is Escherichia coli, followed by Enterococcus and Klebsiella pneumoniae. Patients with Escherichia coli infection are often positive for nitrite before surgery, mainly manifested by high fever, and PCT is significantly increased (often exceeded 100 ng/ml). Enterococcus faecium and Klebsiella pneumoniae infections mostly occur in elderly patients and often progress to septic shock. Patients with Enterococcus faecium infection have a high fever, and the PCT value is significantly higher (often exceeded 20 ng/ml). Patients with Klebsiella pneumoniae infection have a moderate fever, and the PCT value generally does not exceeded 10 ng/ml. Long operation time is another independent risk factor for PCNL infection.

Modelling of the transmission dynamics of carbapenem-resistant Klebsiella pneumoniae in hospitals and design of control strategies

Carbapenem-resistant Klebsiella pneumoniae (CRKP) has emerged as a major threat to global public health. Epidemiological and infection controls associated with CRKP are challenging because of several potential elements involved in a complicated cycle of transmission. Here, we proposed a comprehensive mathematical model to investigate the transmission dynamics of CRKP, determine factors affecting the prevalence, and evaluate the impact of interventions on transmission. The model includes the essential compartments, which are uncolonized, asymptomatic colonized, symptomatic colonized, and relapsed patients. Additionally, symptomatic colonized and relapsed patients were further classified into subpopulations according to their number of treatment failures or relapses. We found that the admission of colonized patients and use of antibiotics significantly impacted the endemic transmission in health care units. Thus, we introduced the treatment efficacy, defined by combining the treatment duration and probability of successful treatment, to characterize and describe the effects of antibiotic treatment on transmission. We showed that a high antibiotic treatment efficacy results in a significantly reduced likelihood of patient readmission in the health care unit. Additionally, our findings demonstrate that CRKP transmission with different epidemiological characteristics must be controlled using distinct interventions.

Phage Therapy Experience at the Eliava Phage Therapy Center: Three Cases of Bacterial Persistence

In this retrospective descriptive study we focus on cases of three patients who underwent phage therapy procedures at Eliava Phage Therapy Center (EPTC) in Tbilisi, Georgia. Patients with chronic infectious diseases related to Pseudomonas aeruginosa (two patients, lower respiratory tract infection (LRTI)) and Klebsiella pneumoniae (one patient, urinary tract infection (UTI)) are among those very few EPTC patients whose pathogens persisted through phage therapy. By looking at bacterial strains and personalized phages used against them we tried to point towards possible adaptation strategies that are employed by these pathogens. Genome restriction-based Pulsed Field Gel Electrophoresis (PFGE) profiling of strains isolated before and after phage therapy hints towards two strategies of adaptation. In one patient case (Pseudomonas aeruginosa related lung infection) bacterial strains before and after phage therapy were indistinguishable according to their PFGE profiles, but differed in their phage susceptibility properties. On the other hand, in two other patient cases (Pseudomonas aeruginosa related LRTI and Klebsiella pneumoniae related UTI) bacterial adaptation strategy seemed to have resulted in diversification of infecting strains of the same species. With this work we want to attract more attention to phage resistance in general as well as to its role in phage therapy.

Pathogen distribution and risk factors for urinary tract infection in infants and young children with retained double-J catheters

Objectives

To investigate the pathogens and potential risk factors for urinary tract infection (UTI) in patients with retained double-J catheters (DJCs).

Methods

In total, 107 infants and young children with DJCs were included in this retrospective analysis. Patients were included in the infection group (n = 30) or non-infection group (n = 77), according to UTI presence or absence. The species and characteristics of pathogens were investigated, and the clinical features of the patients were recorded for further analysis.

Results

Gram-negative bacilli were the most common causative pathogens (69.2%), among which Escherichia coli was most frequent (38.5%). The second most common causative pathogens were Gram-positive cocci (28.2%), among which Enterococcus faecalis was most frequent (10.3%). UTIs among patients in this study were associated with the following factors: catheter retention (long-term) (odds ratio [OR] = 2.514, 95% confidence interval [CI] = 1.176–5.373), sex (male) (OR = 2.966, 95% CI = 1.032–8.529), DJC retention (long-term) (OR = 1.869, 95% CI = 1.194–2.926), and DJC number (unilateral) (OR = 0.309, 95% CI = 0.103–0.922).

Conclusions

Infants and young children with DJCs were likely to experience UTIs, mainly caused by Gram-negative bacilli. Long-term catheter retention or DJC retention, male sex, and bilateral DJC retention were risk factors for UTI.

Comparative Genomics of Escherichia coli Sequence Type 219 Clones From the Same Patient: Evolution of the IncI1 blaCMY-Carrying Plasmid in Vivo

This study investigates the evolution of an Escherichia coli sequence type 219 clone in a patient with recurrent urinary tract infection, comparing isolate EC974 obtained prior to antibiotic treatment and isolate EC1515 recovered after exposure to several β-lactam antibiotics (ceftriaxone, cefixime, and imipenem). EC974 had a smooth colony morphology, while EC1515 had a rough colony morphology on sheep blood agar. RAPD-PCR analysis suggested that both isolates belonged to the same clone. Antimicrobial susceptibility tests showed that EC1515 was more resistant to piperacillin/tazobactam, cefepime, cefpirome, and ertapenem than EC974. Comparative genomic analysis was used to investigate the genetic changes of EC974 and EC1515 within the host, and showed three plasmids with replicons IncI1, P0111, and IncFII in both isolates. P0111-type plasmids pEC974-2 and pEC1515-2, contained the antibiotic resistance genes aadA2, tetA, and drfA12. IncFII-type plasmids pEC974-3 and pEC1515-3 contained the antibiotic resistance genes bla_TEM−1, aadA1, aadA22, sul3, and inuF. Interestingly, bla_CMY−111 and bla_CMY−4 were found in very similar IncI1 plasmids that also contained aadA22 and aac(3)-IId, from isolates EC974 (pEC974-1) and EC1515 (pEC1515-1), respectively. The results showed in vivo amino acid substitutions converting bla_CMY−111 to bla_CMY−4 (R221W and A238V substitutions). Conjugation experiments showed a high frequency of IncI1 and IncFII plasmid co-transference. Transconjugants and DH5α cells harboring bla_CMY-₄ or bla_CMY-₁₁₁ showed higher levels of resistance to ampicillin, amoxicillin, cefazolin, cefuroxime, cefotaxime, cefixime, and ceftazidime, but not piperacillin/tazobactam, cefpime, or ertapenem. All known genes (outer membrane proteins and extended-spectrum AmpC β-lactamases) involved in ETP resistance in E. coli were identical between EC974 and EC1515. This is the first study to identify the evolution of an IncI1 plasmid within the host, and to characterize bla_CMY−111 in E. coli.

Microbial Diversity of Source and Point-of-Use Water in Rural Haiti - A Pyrosequencing-Based Metagenomic Survey

Haiti endures the poorest water and sanitation infrastructure in the Western Hemisphere, where waterborne diseases cause significant morbidity and mortality. Most of these diseases are reported to be caused by waterborne pathogens. In this study, we examined the overall bacterial diversity of selected source and point-of-use water from rural areas in Central Plateau, Haiti using pyrosequencing of 16s rRNA genes. Taxonomic composition of water samples revealed an abundance of Firmicutes phyla, followed by Proteobacteria and Bacteroidetes. A total of 38 bacterial families and 60 genera were identified. The presence of several Klebsiella spp. (tentatively, K. pneumoniae, K. variicola and other Klebsiella spp.) was detected in most water samples. Several other human pathogens such as Aeromonas, Bacillus, Clostridium, and Yersinia constituted significantly higher proportion of bacterial communities in the point-of-use water samples compared to source water. Bacterial genera traditionally associated with biofilm formation, such as Chryseobacterium, Fusobacterium, Prevotella, Pseudomonas were found in the point-of-use waters obtained from water filters or domestic water storage containers. Although the pyrosequencing method utilized in this study did not reveal the viability status of these pathogens, the abundance of genetic footprints of the pathogens in water samples indicate the probable risk of bacterial transmission to humans. Therefore, the importance of appropriate handling, purification, and treatment of the source water needed to be clearly communicated to the communities in rural Haiti to ensure the water is safe for their daily use and intake.

Essential Oils and Their Components as Modulators of Antibiotic Activity against Gram-Negative Bacteria

Gram-negative bacteria cause infections that are difficult to treat due to the emergence of multidrug resistance. This review summarizes the current status of the studies investigating the capacity of essential oils and their components to modulate antibiotic activity against Gram-negative bacteria. Synergistic interactions are particularly discussed with reference to possible mechanisms by which essential oil constituents interact with antibiotics. Special emphasis is given to essential oils and volatile compounds that inhibit efflux pumps, thus reversing drug resistance in Gram-negative bacteria. In addition, indifference and antagonism between essential oils/volatile compounds and conventional antibiotics have also been reported. Overall, this literature review reveals that essential oils and their purified components enhance the efficacy of antibiotics against Gram-negative bacteria, being promising candidates for the development of new effective formulations against Gram-negative bacteria.

Progressive increase of resistance in Enterobacteriaceae urinary isolates from kidney transplant recipients over the past decade: narrowing of the therapeutic options

BACKGROUND

Antibiotic resistance is an emerging phenomenon in kidney transplantation (KT).

METHODS

We compared species distribution and antimicrobial susceptibility patterns in 1052 isolates from urine cultures obtained in 2 different cohorts of kidney transplant recipients in a single center (Cohort A: 189 patients undergoing KT between January 2002 and December 2004 [336 isolates]; Cohort B: 115 patients undergoing KT between January 2011 and December 2013 [716 isolates]).

RESULTS

Asymptomatic bacteriuria accounted for most of the isolates (86.9% in Cohort A and 92.3% in Cohort B). Klebsiella pneumoniae (9.5% vs. 15.6%), Pseudomonas aeruginosa (1.8% vs. 7.9%), and Enterobacter cloacae (0.6% vs. 3.1%) were significantly more common in Cohort B. The isolation of K. pneumoniae in Cohort B was associated with the occurrence of acute pyelonephritis (9.8% of all K. pneumoniae isolates vs. 2.8% of the remaining uropathogens; P = 0.001). Non-susceptibility rates among Enterobacteriaceae in Cohort B were higher for every class of antibiotics (P ≤ 0.003) with the exception of fosfomycin. Compared to Cohort A, significant increases were seen in isolates from Cohort B for multidrug-resistant (MDR) (43.9% vs. 67.8%, respectively; P = 0.001), extended-spectrum beta-lactamase (ESBL)-producing (6.6% vs. 26.1%; P = 0.001), and carbapenemase-producing Enterobacteriaceae strains (0.0% vs. 5.0%; P = 0.001). Such differences were mostly attributable to K. pneumoniae (as 54.5% and 13.4% of isolates in Cohort B were ESBL-producing and carbapenemase-producing, respectively). MDR isolates were responsible for 69.1% of episodes of symptomatic urinary tract infection in Cohort B.

CONCLUSION

The increase in resistance rates among Enterobacteriaceae uropathogens is significant and may have an effect on KT programs.

Klebsiella pneumoniae: Going on the Offense with a Strong Defense

Klebsiella pneumoniae causes a wide range of infections, including pneumonias, urinary tract infections, bacteremias, and liver abscesses. Historically, K. pneumoniae has caused serious infection primarily in immunocompromised individuals, but the recent emergence and spread of hypervirulent strains have broadened the number of people susceptible to infections to include those who are healthy and immunosufficient. Furthermore, K. pneumoniae strains have become increasingly resistant to antibiotics, rendering infection by these strains very challenging to treat. The emergence of hypervirulent and antibiotic-resistant strains has driven a number of recent studies. Work has described the worldwide spread of one drug-resistant strain and a host defense axis, interleukin-17 (IL-17), that is important for controlling infection. Four factors, capsule, lipopolysaccharide, fimbriae, and siderophores, have been well studied and are important for virulence in at least one infection model. Several other factors have been less well characterized but are also important in at least one infection model. However, there is a significant amount of heterogeneity in K. pneumoniae strains, and not every factor plays the same critical role in all virulent Klebsiella strains. Recent studies have identified additional K. pneumoniae virulence factors and led to more insights about factors important for the growth of this pathogen at a variety of tissue sites. Many of these genes encode proteins that function in metabolism and the regulation of transcription. However, much work is left to be done in characterizing these newly discovered factors, understanding how infections differ between healthy and immunocompromised patients, and identifying attractive bacterial or host targets for treating these infections.

Dissemination of multidrug-resistant blaCTX-M-15/IncFIIk plasmids in Klebsiella pneumoniae isolates from hospital- and community-acquired human infections in Tunisia

This study investigated the molecular features of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae from hospital- and community-acquired (HA/CA) infections in the region of Mahdia, Tunisia. Among 336 K. pneumoniae isolates recovered from both clinical contexts between July 2009 and December 2011, 49 and 15 were ESBL producers and originated from clinical and community sources, respectively. All isolates produced the CTX-M-15 enzyme. As shown by Southern blot on S1 nuclease treatment followed by pulsed-field gel electrophoresis (PFGE) gels, the blaCTX-M-15 gene was carried on IncFII (n=4), IncFIIk (n=25), IncL/M (n=4), IncK (n=1), or untypeable (n=15) plasmids in HA isolates. In CA isolates, the blaCTX-M-15 gene was carried on IncFIIk (n=6), IncFII (n=1), IncHI1 (n=1), or untypeable (n=7) plasmids. In all, 23 and 11 PFGE types were found among the HA and CA isolates. Multilocus sequence typing on representative isolates shows diverse sequence types (STs), such as ST307, ST101, ST39, ST4, ST140, ST15, and ST307 in HA isolates and ST101, ST664, and ST323 in CA isolates. This study is the first comprehensive report of ESBL plasmids in K. pneumoniae from HA and CA infections in Tunisia.

Transfer of CMY-2 Cephalosporinase from Escherichia coli to Virulent Klebsiella pneumoniae Causing a Recurrent Liver Abscess

A CMY-2-producing capsular type K2 Klebsiella pneumoniae strain (TVGHKP93) with multidrug resistance was isolated from a recurrent liver abscess in a patient who also carried a CMY-2-producing Escherichia coli strain (TVGHEC01) in the stool. TVGHKP93 retained its high virulence compared with that of the isogenic strain (TVGHKP60) with wild-type resistance from the first liver abscess. Our conjugation experiment showed the successful transfer of the blaCMY-2-carrying plasmid from TVGHEC01 into TVGHKP60. The transconjugant showed both high virulence and the multidrug-resistant phenotype, as did TVGHKP93.

Diversity of bacterial communities of fitness center surfaces in a U.S. metropolitan area

Public fitness centers and exercise facilities have been implicated as possible sources for transmitting community-acquired bacterial infections. However, the overall diversity of the bacterial community residing on the surfaces in these indoor environments is still unknown. In this study, we investigated the overall bacterial ecology of selected fitness centers in a metropolitan area (Memphis, TN, USA) utilizing culture-independent pyrosequencing of the 16S rRNA genes. Samples were collected from the skin-contact surfaces (e.g., exercise instruments, floor mats, handrails, etc.) within fitness centers. Taxonomical composition revealed the abundance of Firmicutes phyla, followed by Proteobacter and Actinobacteria, with a total of 17 bacterial families and 25 bacterial genera. Most of these bacterial genera are of human and environmental origin (including, air, dust, soil, and water). Additionally, we found the presence of some pathogenic or potential pathogenic bacterial genera including Salmonella, Staphylococcus, Klebsiella, and Micrococcus. Staphylococcus was found to be the most prevalent genus. Presence of viable forms of these pathogens elevates risk of exposure of any susceptible individuals. Several factors (including personal hygiene, surface cleaning and disinfection schedules of the facilities) may be the reasons for the rich bacterial diversity found in this study. The current finding underscores the need to increase public awareness on the importance of personal hygiene and sanitation for public gym users.

Antibiotic Resistance Related to Biofilm Formation in Klebsiella pneumoniae

The Gram-negative opportunistic pathogen, Klebsiella pneumoniae, is responsible for causing a spectrum of community-acquired and nosocomial infections and typically infects patients with indwelling medical devices, especially urinary catheters, on which this microorganism is able to grow as a biofilm. The increasingly frequent acquisition of antibiotic resistance by K. pneumoniae strains has given rise to a global spread of this multidrug-resistant pathogen, mostly at the hospital level. This scenario is exacerbated when it is noted that intrinsic resistance to antimicrobial agents dramatically increases when K. pneumoniae strains grow as a biofilm. This review will summarize the findings about the antibiotic resistance related to biofilm formation in K. pneumoniae.