Plasmid-mediated extended-spectrum beta-lactamase-producing strains of Enterobacteriaceae isolated from diabetes foot infections in a Brazilian diabetic center

Surveillance of Enterobacteriaceae from Diabetic Foot Infections in a Tunisian Hospital: Detection of E. coli-ST131-blaCTX-M-15 and K. pneumoniae-ST1-blaNDM-1 Strains

The study determined the prevalence, antimicrobial resistant (AMR) determinants, and genetic characteristics of Escherichia coli and Klebsiella pneumoniae isolates from patients with diabetic foot infection (DFI) in a Tunisian hospital. A total of 26 Escherichia spp. and Klebsiella spp. isolates were recovered and identified by MALDI-TOF-MS. Antimicrobial susceptibility testing, the detection of AMR determinants and Shiga-like toxin genes, phylogenetic grouping, and molecular typing were performed. Twelve E. coli, 10 K. pneumoniae, 3 K. oxytoca, and 1 E. hermanii were isolated. A multidrug-resistant phenotype was detected in 65.4% of the isolates. About 30.8% of isolates were extended-spectrum β-lactamase (ESBL) producers and mainly carried blaCTX-M-15 and blaCTX-M-14 genes. One blaNDM-1-producing K. pneumoniae-ST1 strain was identified. Class 1 integrons were detected in 11 isolates and 5 gene cassette arrangements were noted: dfrA1+aadA1 (n = 1), dfrA12+aadA2 (n = 3), and dfrA17+aadA5 (n = 1). Other non-β-lactam resistance genes detected were as follows (number of isolates): aac(3')-II (3), aac(6')-Ib-cr(8), qnrB (2), qnrS (4), cmlA (2), floR (4), sul1 (11), sul2 (11), and sul3 (2). The phylogroup B1 was the most frequent (41.7%) among E. coli, and two ESBL-producing isolates corresponded to the ST131-B2 lineage. The ESBL- and carbapenemase-producing Enterobacteriaceae in DFIs are described for the first time in Tunisia.

Virulence and antimicrobial resistance profile of non-typhoidal Salmonella enterica serovars recovered from poultry processing environments at wet markets in Dhaka, Bangladesh

The rapid emergence of virulent and multidrug-resistant (MDR) non-typhoidal Salmonella (NTS) enterica serovars is a growing public health concern globally. The present study focused on the assessment of the pathogenicity and antimicrobial resistance (AMR) profiling of NTS enterica serovars isolated from the chicken processing environments at wet markets in Dhaka, Bangladesh. A total of 870 samples consisting of carcass dressing water (CDW), chopping board swabs (CBS), and knife swabs (KS) were collected from 29 wet markets. The prevalence of Salmonella was found to be 20% in CDW, 19.31% in CBS, and 17.58% in KS, respectively. Meanwhile, the MDR Salmonella was found to be 72.41%, 73.21%, and 68.62% in CDW, CBS, and KS, respectively. All isolates were screened by polymerase chain reaction (PCR) for eight virulence genes, namely invA, agfA, IpfA, hilA, sivH, sefA, sopE, and spvC. The S. Enteritidis and untyped Salmonella isolates harbored all virulence genes while S. Typhimurium isolates carried six virulence genes, except sefA and spvC. Phenotypic resistance revealed decreased susceptibility to ciprofloxacin, streptomycin, ampicillin, tetracycline, gentamicin, sulfamethoxazole-trimethoprim, amoxicillin-clavulanic acid, and azithromycin. Genotypic resistance showed a higher prevalence of plasmid-mediated blaTEM followed by tetA, sul1, sul2, sul3, and strA/B genes. The phenotypic and genotypic resistance profiles of the isolates showed a harmonic and symmetrical trend. According to the findings, MDR and virulent NTS enterica serovars predominate in wet market conditions and can easily enter the human food chain. The chi-square analysis showed significantly higher associations among the phenotypic resistance, genotypic resistance and virulence genes in CDW, CBS, and KS respectively (p < 0.05).

Aerobic bacteria isolated from diabetic foot ulcers of Egyptian patients: types, antibiotic susceptibility pattern and risk factors associated with multidrug-resistant organisms

INTRODUCTION

Diabetic foot infection (DFI) is one of the common diabetic complications. Pathogens causing DFI and their antibiotic susceptibility vary with location. Therefore, empirical antibiotic therapy should be based on the pathogens that are most likely to be present. Aim: To identify the frequent aerobic bacteria causing DFI with detection of their antibiotic susceptibility to help clinicians in our community choose the best empirical antibiotic for DFI.

METHODS

Swabs were collected from 104 diabetic foot ulcers (DFUs). Aerobic bacterial cultures were done followed by bacterial identification and antibiotic susceptibility testing on VITEK® 2 system. Extended-spectrum beta-lacatamase (ESBL) detection was performed phenotypically and confirmed by multiplex-PCR for bla _CTX-M, bla _TEM, and bla _SHV genes.

RESULTS

Aerobic bacterial infection was detected in 82/104 (78.8%) of the DFUs. Gram-negative bacilli (GNB) were isolated more frequently (56.1%) than Gram-positive cocci (GPC) (43.9%). The most common single-isolated bacteria were K. pneumoniae (26.8%), S. aureus and coagulase negative staphylococci (22% for each). The only significant independent predictors of DFI with GNB or GPC were long DM duration and frequent hospitalizations, respectively. The most active antibiotics were amikacin, tigecycline and meropenem for GNB, and linezolid and vancomycin for staphylococci. Multidrug-resistance prevalence was 95.1%. ESBL was detected in 52.6% of Enterobacteriaceae; the bla _CTX-M gene was the most common (90%), followed by bla _TEM (65%) and bla _SHV (35%). Peripheral neuropathy was the single independent predictor for DFI with ESBL producers (adjusted OR=15.5).

CONCLUSIONS

There is a notable local pattern of DFI bacteriology in our community. Our findings could be valuable in developing the future empirical treatment guidelines for DFIs.

Virulence and Antimicrobial Resistance Profiles of Salmonella enterica Serovars Isolated from Chicken at Wet Markets in Dhaka, Bangladesh

Virulent and multi drug resistant (MDR) Salmonellaenterica is a foremost cause of foodborne diseases and had serious public health concern globally. The present study was undertaken to identify the pathogenicity and antimicrobial resistance (AMR) profiles of Salmonellaenterica serovars recovered from chicken at wet markets in Dhaka, Bangladesh. A total of 870 cecal contents of broiler, sonali, and native chickens were collected from 29 wet markets. The overall prevalence of S. Typhimurium, S. Enteritidis, and untyped Salmonella spp., were found to be 3.67%, 0.57%, and 1.95% respectively. All isolates were screened by polymerase chain reaction (PCR) for eight virulence genes, namely invA, agfA, IpfA, hilA, sivH, sefA, sopE, and spvC. S. Enteritidis isolates carried all virulence genes whilst S. Typhimurium isolates carried six virulence genes except sefA and spvC. A diverse phenotypic and genotypic AMR pattern was found. Harmonic descending trends of resistance patterns were observed among the broiler, sonali, and native chickens. Interestingly, virulent and MDR Salmonella enterica serovars were found in native chicken, although antimicrobials were not used in their production cycle. The research findings anticipate that virulent and MDR Salmonella enterica are roaming in the wet markets which can easily anchor to the vendor, consumers, and in the food chain.

Metatranscriptomic Analysis Reveals Active Bacterial Communities in Diabetic Foot Infections

Despite the extended view of the composition of diabetic foot infections (DFIs), little is known about which transcriptionally active bacterial communities are pertinent to infection, and if any differences are associated with increased infection severity. We applied a RNA sequencing approach to analyze the composition, function, and pathogenicity of the active bacterial communities in DFIs. Taxonomic profiling of bacterial transcripts revealed the presence of 14 bacterial phyla in DFIs. The abundance of the Spiroplasma, Vibrio, and Mycoplasma were significantly different in different infection severities (P < 0.05). Mild and severe stages of infections were dominated by Staphylococcus aureus and Porphyromonas asaccharolytica, respectively. A total of 132 metabolic pathways were identified of which ribosome and thiamin being among the most highly transcribed pathways. Moreover, a total of 131 antibiotic resistance genes, primarily involved in the multidrug efflux pumps/exporters, were identified. Furthermore, iron acquisition systems (synthesize and regulation of siderophores) and pathways involved in the synthesis and regulation of cell-surface components associated with adhesion, colonization, and movement of bacterial cells were the most common virulence factors. These virulence factors may help bacteria compete for scares resources and survive the host wound proteases. Characterization of transcriptionally active bacterial communities can help to provide an understanding of the role of key pathogens in the development of DFIs. Such information can be clinically useful allowing replacement of DFIs empirical therapy with targeted treatment.

High Frequency of Extended-Spectrum Beta-Lactamase-Producing Klebsiella pneumoniae Nosocomial Strains Isolated from a Teaching Hospital in Brazil

The aim of this study was to investigate the frequency, antimicrobial sensitivity profile, and genetic characteristics of nosocomial strains of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae isolated from inpatients at a teaching hospital in Brazil. The bacterial identification, phenotypic detection of ESBL, and antimicrobial susceptibility profile were performed by the VITEK 2 automated system. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) mass spectrometry was used to confirm the identity of the species and genotyping of ESBL-producing K. pneumoniae was performed by pulsed-field gel electrophoresis (PFGE). Thirty-six ESBL-producing K. pneumoniae nosocomial strains isolated from November 2013 to August 2014 were analyzed. High resistance rates were observed for ceftriaxone, ceftazidime, cefepime, gentamicin, and ciprofloxacin. However, all isolates were susceptible to amikacin and meropenem. All strains harbored bla_CTX-M-like and bla_SHV-like genes. Molecular typing by PFGE showed a diversity of genotypes distributed among 25 clusters, but two isolates collected in different wards had the same genotypic profile and carried the same bla genes, so they were considered clones. The data showed that there was a high frequency of ESBL-producing K. pneumoniae multidrug-resistant among patients in the studied hospital. Furthermore, the detection of bla_CTX-M-like genes in all isolates suggests that these enzymes are the major ESBL responsible for the beta-lactam resistance phenotypes among the analyzed strains.

Microbial profile of diabetic foot infections in Trinidad and Tobago

AIMS

To examine the microbiologic profile of diabetic foot infections in order to guide empiric antibiotic choices.

METHODS

All patients with moderate-severe diabetic foot infections at a tertiary care facility were identified from July 2011 to June 2012. Culture samples were routinely collected before empiric antibiotics were commenced. Retrospective chart review was performed to extract the following data: demographics, clinical details, empiric antibiotic choice and microbiologic data. Descriptive analyses were performed using SPSS 12.0.

RESULTS

There were 139 patients at a mean age of 56.9 ± 12.4 years. Mixed poly-microbial infections were present in 56.8% of cases. Of 221 organisms isolated, 64.7% were gram-negative aerobes, 32.1% were gram-positive aerobes and 3.2% were obligate anaerobes. Multidrug resistant organisms were encountered in 25.9% of cases and included ESBL producers (11.3%), MRSA (4.5%) and VRE (1.4%). Both ciprofloxacin and ceftazidime had good overall anti-microbial activity against gram-negative (68% and 62%, respectively) and gram-positive pathogens (69% and 48%, respectively). Obligate anaerobes were uncommonly isolated due to institutional constraints.

CONCLUSION

In this environment, both ciprofloxacin and ceftazidime provide good broad-spectrum anti-microbial activity against the commonly isolated pathogens. Either agent can be used as single agent empiric therapy in patients with moderate/severe diabetic infections in our setting. Although institutional limitations precluded isolation of anaerobes in most cases, there is sufficient evidence for anti-anaerobic agents to be recommended as a part of empiric therapy.

Detection of Escherichia coli and associated β-lactamases genes from diabetic foot ulcers by multiplex PCR and molecular modeling and docking of SHV-1, TEM-1, and OXA-1 β-lactamases with clindamycin and piperacillin-tazobactam

Diabetic foot ulcer (DFU) is a common and devastating complication in diabetes. Antimicrobial resistance mediated by extended-spectrum β-lactamases (ESBLs) production by bacteria is considered to be a major threat for foot amputation. The present study deals with the detection of Escherichia coli and the prevalence of bla_TEM, bla_SHV and bla_OXA genes directly from biopsy and swab of foot ulcers of diabetic patients. In total, 116 DFU patients were screened, of which 42 suffering with severe DFUs were selected for this study. Altogether 16 E. coli strains were successfully isolated from biopsy and/or swab samples of 15 (35.71%) patients. ESBL production was noted in 12 (75%) strains. Amplification of β-lactamase genes by multiplex PCR showed the presence of bla_CTX-M like genes in 10 strains, bla_TEM and bla_OXA in 9 strains each, and bla_SHV in 8 of the total 16 strains of E. coli. Out of the ten antibiotics tested, E. coli strains were found to be resistant to ampicillin (75%), cefoxitin (56.25%), cefazolin (50%), meropenem (37.5%), cefoperazone (25%), cefepime (31.25%), ceftazidime (56.25%), and cefotaxime (68.75%) but all showed sensitivity (100%) to clindamycin and piperacillin-tazobactam. 3D models of the most prevalent variants of β-lactamases namely TEM-1, SHV-1, OXA-1, and ESBL namely CTX-M-15 were predicted and docking was performed with clindamycin and piperacillin-tazobactam to reveal the molecular basis of drug sensitivity. Docking showed the best docking score with significant interactions, forming hydrogen bond, Van der Waals and polar level interaction with active site residues. Findings of the present study may provide useful insights for the development of new antibiotic drugs and may also prevent ESBLs-mediated resistance problem in DFU. The novel multiplex PCR assay designed in this study may be routinely used in clinical diagnostics of E. coli and associated bla_TEM, bla_SHV, and bla_OXA like genes.

Bacteriological and resistance profile in isolates from diabetic patients

BACKGROUND

Diabetes mellitus has become a global epidemic illness and poses a threat for development of resistant bacterial infections.

AIM

This study was aimed to know the bacteriological and resistance profile of isolates obtained from diabetic patients.

MATERIALS AND METHODS

The bacterial isolates obtained from various samples of diabetic patients admitted in medicine department in 6-month period were identified and tested for antibiotic susceptibility. The extended spectrum beta-lactamases (ESβL), AmpC, and metallo-beta-lactamases (MβL) enzymes were detected in gram-negative bacilli. Methicillin, macrolide-lincosamide-streptogramin (MLS), and linezolid resistance in Staphylococcus spp. were detected. High-level aminoglycoside resistance (HLAR) in Enterococcus spp. was also tested.

RESULTS

In all, 38 of 125 diabetic patients (30.4%) had bacterial infection, 18 patients had wound infections, 18 had urinary tract infections (UTIs), and 2 had respiratory tract infections. Escherichia coli among gram-negative bacteria and Staphylococcus aureus among gram-positive bacteria were the predominant pathogens. 32.5% gram-negative bacilli were AmpC producers, 37.5% were MβL producers, and 40% were ESβL producers. Methicillin and MLS resistance was found in 50% and 33.3% isolates of Staphylococcus spp., respectively. HLAR resistance was alarming in Enterococcus spp. Polymyxin among gram-negative bacteria and vancomycin for gram-positive bacteria were the last resort with highest susceptibility rates to treat infections among diabetic patients.

CONCLUSION

Resistant bacterial infections in diabetic patients are common. The presence of various resistance mechanisms in isolates of our study shows that therapeutic failure can occur if empirical prescription is unsubstantiated.

CTX-M-producing Escherichia coli and Klebsiella pneumoniae isolated from community-acquired urinary tract infections in Valledupar, Colombia

OBJECTIVE

Describe the presence of CTX-M-1 phylogenetic subgroup extended-spectrum β-lactamases (ESBL), associated with TEM and SHV genes, and the gene encoding cephalosporinase, CMY-2 in Escherichia coli and Klebsiella pneumoniae isolates from community-acquired urinary tract infections.

METHODS

102 E. coli and 21K. pneumoniae were collected from patients with culture-proven urinary tract infection (UTI), during February and March, 2011. Antimicrobial susceptibility test was performed by disk diffusion according to the standards of the Clinical Laboratory Standard Institute. Screening for cephalosporins-resistant E. coli and K. pneumoniae was performed by PCR assay for bla(TEM), bla(SHV), bla(CTX-M-1),(-2),(-8),(-9), bla(PER-2) and bla(CMY-2) genes. Statistical analysis was performed by chi-squared test and multivariate logistic regression analysis.

RESULTS

ESBL production was detected in 12 (11.7%) E. coli and four (19%) K. pneumoniae isolates. TEM ESBLs were detected in seven E. coli and three K. pneumoniae isolates. SHV ESBLs were found in four K. pneumoniae isolates. CTX-M-1 phylogenetic subgroup was positive in seven E. coli and three K. pneumoniae isolates. CMY-2 β-lactamase gene was detected in nine E. coli and one K. pneumoniae isolates. A significant association of ESBL expression in E. coli was observed with resistance to tobramycin (p≤0.001), tetracycline (p=0.043), and ciprofloxacin (p≤0.001). In K. pneumoniae isolates, significant association was found with resistance to tobramycin and ciprofloxacin (p=0.006), and trimethoprim-sulfamethoxazole (p=0.043). Multivariate analyses did not show association between ESBL production in E. coli and K. pneumoniae, and resistance to non-β-lactams drugs.

CONCLUSIONS

CTX-M ESBL in uropathogens isolated from the community is cause for concern due to the enormous potential for multidrug resistance from strains that produce these enzymes, which could lead to failure of empirically-administered therapies and development of complicated UTIs.

A case report of a multi-drug resistant bacterial infection in a diabetic patient treated in northeast Brazil

Diabetes mellitus is one of the most critical health conditions around the world, not only in terms of the number of affected people, disability, and premature mortality, but also in regards to the health care costs involved in controlling and treating its complications. Among the most constant ailments the diabetic patient suffers is the diabetic foot, defined as any infection, ulceration, and/or necrosis of deep tissues associated with neurological abnormalities and various degrees of peripheral vascular disease of the lower limbs. Diabetic foot ulcerations have become a major and increasing public health concern and its associated morbidities, impairment of the patients' quality of life, and the implied costs for management have attracted the attention of numerous health care providers. In this case report, the authors review a unique presentation of a polymicrobial infection of a multi-drug resistant character species formed by oxacillin-resistant Staphylococcus aureus, Acinetobacter baumannii and Acinetobacter lwoffii.

Clinico-microbiological study and antimicrobial drug resistance profile of diabetic foot infections in North India

The study was carried out in diabetic patients with foot ulcer to determine the microbiological profile of infected ulcer, antibiotic resistance of the isolates and to find out the potential risk factors for infection with multidrug resistance and the outcome of these infections. A detailed clinical history and physical examination was carried out in each patient. Pus samples for bacterial culture were collected from 102 patients admitted with diabetic foot infections. All patients had ulcer with Texas grades 1-3. Seventeen patients (16.6%) had coexisting osteomyelitis. Aerobic gram negative bacilli were tested for extended spectrum β lactamase (ESBL) production by phenotypic and genotypic methods. Staphylococcus isolates were tested for susceptibility to oxacillin and cefoxitin by disk method. Potential risk factors for MDRO positive samples were explored. Gram negative aerobes were most frequently isolated (63.8%), followed by gram positive aerobes (36.1%) and anaerobes (31.4%). Forty five percent of patients were positive for MDROs. ESBL production and methicillin resistant was noted in 68.5% and 43.2% of bacterial isolates respectively. 34.5% gram negative strains were positive for bla(CTX-M) gene followed by bla(SHV) (23%) and bla(TEM) (7.4%). Among the anaerobic organism 17(31.4%) from 54 patients, most commonly isolated were Peptostreptococcus sp. (35.2%). MDRO positive status was associated with the presence of neuropathy (P<0.001), osteomyelitis (P<0.03), and ulcer size >4 cm(2) (P<0.01) [corrected] but not with patients characteristic, ulcer type and type of diabetes, or duration of hospital stay. Poor glycemic control in 68.6% patients, duration of infection>1 month (36.2%) and ulcer size >4 cm(2) (75.4%) were independently associated with risk of MDR organisms infection.

Morganella morganii-associated arthritis in a diabetic patient

This case report involves a 60-year-old diabetic man who developed septic arthritis as a result of the pathogen Morganella morganii. The patient had complaints of elevated body temperature, malaise, rigors and pain in the left knee, despite no history of trauma. On examination of the knee, erythema, warmth, tenderness and swelling was observed. Arthrocentesis performed on his left knee indicated the presence of straw-coloured, cloudy fluid without crystals. Bacterial identification based on biochemical and automated methods indicated the growth of M morganii. M morganii was also isolated sedimentafrom the exudate of a diabetic ulcer in the left foot, with antibiotic susceptibilities identical to those from the knee effusion. This case indicates that M morganii may be considered as a possible cause of septic arthritis in diabetic patients, especially those with diabetic foot infections.

Prevalence of community-occurring extended spectrum beta-lactamase-producing Enterobacteriaceae in Brazil

The occurrence of extended-spectrum-beta-lactamase (ESBL)-producing strains in the community was investigated in a private laboratory located in Juiz de Fora, Brazil. All enterobacterial isolates analysed were collected from urine of human patients between the years 2000 and 2002. ESBL production was confirmed by double disk screening, combination disk method, and Etest ESBL strip. The isoelectric point of each beta-lactamase was determined in the crude extracts from each isolate. Detection of ESBL genes was performed by polymerase chain reaction and the genetic relatedness of the isolates determined by pulsed-field gel electrophoresis (PFGE). Of the 1,481 isolates, 22 (12 Klebsiella pneumoniae, 7 Escherichia coli, 1 Providencia stuartii, 1 Citrobacter freundii, and 1 Serratia marcescens) were identified as ESBL producers. The frequency of ESBL producers in the community was 1.48%. TEM-type enzymes were identified in 95.4% of the isolates, followed by the SHV type. Seven strains produced CTX-M-type enzymes. This study showed that strains producing multiple beta-lactamases are also present in community-acquired bacterial isolates. Multiple strains exhibiting identical PFGE genotypes were found in individual patients indicating a common source of acquisition.

Emergence of Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLs) in the community

Enterobacteriaceae, especially Klebsiella spp. producing extended-spectrum beta-lactamases (ESBLs) such as SHV and TEM types, have been established since the 1980s as a major cause of hospital-acquired infections. Appropriate infection control practices have largely prevented the dissemination of these bacteria within many hospitals, although outbreaks have been reported. However, during the late 1990s and 2000s, Enterobacteriaceae (mostly Escherichia coli) producing novel ESBLs, the CTX-M enzymes, have been identified predominantly from the community as a cause of urinary tract infections. Resistance to other classes of antibiotics, especially the fluoroquinolones, is often associated with ESBL-producing organisms. Many clinical laboratories are still not aware of the importance of screening for ESBL-producing Enterobacteriaceae originating from the community. A heightened awareness of these organisms by clinicians and enhanced testing by laboratories, including molecular surveillance studies, is required to reduce treatment failures, to limit their introduction into hospitals and to prevent the spread of these emerging pathogens within the community.