VEB-1 extended-spectrum β-lactamase-producing multidrug-resistant Proteus mirabilis sepsis outbreak in a neonatal intensive care unit in India: clinical and diagnostic implications

Stray Dogs (Mongrels) Are Potent Reservoir of Drug-Resistant Pathogens: A Study in Peri-Urban Areas of Kolkata, India

This study depicts the drug-resistance and phylogenomic characteristics of 365 Escherichia coli (EC) and 76 Klebsiella pneumoniae (KP) isolated from stray dogs (293) in and around Kolkata, India. Initial screening found 59 isolates, including 48 E. coli and 11 KP multidrug resistant, which included 33 extended-spectrum β-lactamase, 41 AmpC β-lactamase and 18 metallo-β-lactamase producers carrying blaNDM-1 (11) and blaNDM-5 (7) genes. Majority of them had the resistant genes such as blaCTX-M (33), blaTEM (18), blaSHV (4), blaOXA (17), blaFOX (2), blaDHA (2), blaCITM (15), blaCMY-2 (13), blaGES (2) and blaVEB (2), qnrS (15), qnrB (3), aac-6'-Ib-cr (14), tetA (26), tetB (14), sul-1 (25), armA (2) and rmtB (6), in addition to adherence genes such as csgA (33), fimA (27), fliC (13), sdiA (33), rcsA (38), and rpoS (39). They also carried plasmid of diverse replicon types of which IncFIA and FIB were the most frequent. Phylogrouping categorized most of the MDR E. coli in phylogroup A (20), B1 (14), and B2 (6). Enterobacteriaceae repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) showed genetic diversity of multidrug resistant isolates irrespective of their origin, resistance, and virulence types, differentiating the EC in five clades (A-E) and KP in four clades (A-D). As these stray dogs, which had no history or scope of previous antimicrobial therapy, were found to have contracted potential antimicrobial resistance pathogens, the role of environment in spread of such pathogens and further possibility of human infections cannot be ruled out.

Infection control measures against multidrug-resistant Gram-negative bacteria in children and neonates

The increase in infections caused by multidrug-resistant (MDR) Gram-negative bacteria in neonatal and pediatric intensive care units over recent years is alarming. MDR Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii have constituted the main causes of the MDR Gram-negative bacteria problem. The implementation of infection control measures such as hand hygiene, cohorting of patients, contact precautions, active surveillance and environmental cleaning could diminish their spread. Recently, water safety has been identified as a major component of infection control policies. The aim of the current review is to highlight the effectiveness of these infection control measures in managing outbreaks caused by MDR Gram-negative bacteria in neonatal and pediatric intensive care units and highlight future perspectives on the topic.

Detection of Carbapenem Resistance of Proteus mirabilis Strains Isolated from Foxes, Raccoons and Minks in China

Proteus mirabilis, an opportunistic pathogen, is found to be an emerging threat to both animals and humans for a variety of infections. However, the characteristics of P. mirabilis infections from foxes, raccoons and minks remain unclear. In this context, we identified the antibiotic resistance genes and virulence genes of P. mirabilis isolates from foxes, raccoons and minks in China. Most isolates showed resistance to florfenicol (90.57%), trimethoprim-sulfamethoxazole (73.58%), and imipenem (71.70%). A total of 73.58% of isolates were resistant to antibiotics from at least three or more classes, and were categorized as multi-drug resistant. A total of 33.33% of the isolates were resistant to antibiotics from seven classes. The most prevalent resistant were sul1 (94.34%), followed by floR, blaTEM, aac(6’)Ib-cr and blaOXA-1 with the detection rate of 88.68%, 83.02%, 71.70% and 60.38%, respectively. Among the 51 P. mirabilis isolates that were resistant to beta-lactam antibiotics, all isolates carried at least one beta-lactam gene. In addition, blaNDM and blaOXA-24 genes were firstly reported in carbapenem-resistant P. mirabilis isolates from foxes, raccoons and minks. All isolates exhibited the virulence genes ureC, zapA, pmfA, atfA and mrpA. P. mirabilis isolates carrying all detected 10 virulence genes from different animal species showed different lethal abilities in a G. mellonella larvae model. More importantly, the profiles of antibiotic resistance genes of isolates from fur animals and the environment were generally similar, and phylogenetic analysis showed that the P. mirabilis isolates from farm environment samples may have close relatedness with that from animals.

Knowledge, Attitudes, and Practices of NICU Doctors and Nurses Toward Prevention and Control of Nosocomial Infection With Multidrug Resistant Organism

BACKGROUND

Nosocomial infection with multidrug resistant organisms (MDRO) can directly influence the curative effect and the prognosis of neonates, bringing great difficulties to clinical treatment. As direct contacts of neonates, the knowledge, attitudes, and practices (KAP) of doctors and nurses are critical for the prevention and control of MDRO infection in neonatal intensive care units (NICUs).

PURPOSE

This study describes the KAP of doctors and nurses in NICUs toward the prevention and control of nosocomial infection with MDRO and analyzes its influencing factors.

METHODS

This cross-sectional study used convenience sampling to survey 397 doctors and nurses from the NICU of 28 hospitals in 11 cities in Zhejiang Province, China. A univariate analysis and a multiple linear regression were used to analyze the data.

RESULTS

The median scoring rate (interquartile range) of the knowledge, attitude, and practice questionnaire was 0.86 (0.82-0.91), 0.98 (0.91-1.00), and 0.995 (0.97-1.00), respectively. However, the median scoring rate regarding "basic knowledge of MDRO" and "special prevention and control measures" was 0.50 in knowledge. The multiple linear regression showed that the influencing factors of KAP were hospital grade, professional title, gender, regular supervision, and training.

CONCLUSIONS

There was still room for improvement in the KAP of NICU doctors and nurses, especially regarding the knowledge. Men, doctors and nurses in Grade II hospitals, and doctors and nurses with primary professional titles had worse KAP. Training and supervision helped improve the KAP.

RELEVANCE TO CLINICAL PRACTICE

To improve the KAP of doctors and nurses to enhance the prevention and control effect for the MDRO infection in NICUs, hospitals and departments should carry out targeted training and strengthen supervision, while Grade II hospitals, men, and doctors and nurses with primary professional titles need more attention.

High Burden of Bloodstream Infections Associated With Antimicrobial Resistance and Mortality in the Neonatal Intensive Care Unit in Pune, India

BACKGROUND

Antimicrobial resistance (AMR) is a growing threat to newborns in low- and middle-income countries (LMIC).

METHODS

We performed a prospective cohort study in 3 tertiary neonatal intensive care units (NICUs) in Pune, India, to describe the epidemiology of neonatal bloodstream infections (BSIs). All neonates admitted to the NICU were enrolled. The primary outcome was BSI, defined as positive blood culture. Early-onset BSI was defined as BSI on day of life (DOL) 0-2 and late-onset BSI on DOL 3 or later.

RESULTS

From 1 May 2017 until 30 April 2018, 4073 neonates were enrolled. Among at-risk neonates, 55 (1.6%) developed early-onset BSI and 176 (5.5%) developed late-onset BSI. The majority of BSIs were caused by gram-negative bacteria (GNB; 58%); among GNB, 61 (45%) were resistant to carbapenems. Klebsiella spp. (n = 53, 23%) were the most common cause of BSI. Compared with neonates without BSI, all-cause mortality was higher among neonates with early-onset BSI (31% vs 10%, P < .001) and late-onset BSI (24% vs 7%, P < .001). Non-low-birth-weight neonates with late-onset BSI had the greatest excess in mortality (22% vs 3%, P < .001).

CONCLUSIONS

In our cohort, neonatal BSIs were most commonly caused by GNB, with a high prevalence of AMR, and were associated with high mortality, even in term neonates. Effective interventions are urgently needed to reduce the burden of BSI and death due to AMR GNB in hospitalized neonates in LMIC.

Extended-spectrum β-lactamases: an update on their characteristics, epidemiology and detection

Extended-spectrum β-lactamase (ESBL)-producing Gram-negative pathogens are a major cause of resistance to expanded-spectrum β-lactam antibiotics. Since their discovery in the early 1980s, they have spread worldwide and an are now endemic in Enterobacterales isolated from both hospital-associated and community-acquired infections. As a result, they are a global public health concern. In the past, TEM- and SHV-type ESBLs were the predominant families of ESBLs. Today CTX-M-type enzymes are the most commonly found ESBL type with the CTX-M-15 variant dominating worldwide, followed in prevalence by CTX-M-14, and CTX-M-27 is emerging in certain parts of the world. The genes encoding ESBLs are often found on plasmids and harboured within transposons or insertion sequences, which has enabled their spread. In addition, the population of ESBL-producing Escherichia coli is dominated globally by a highly virulent and successful clone belonging to ST131. Today, there are many diagnostic tools available to the clinical microbiology laboratory and include both phenotypic and genotypic tests to detect β-lactamases. Unfortunately, when ESBLs are not identified in a timely manner, appropriate antimicrobial therapy is frequently delayed, resulting in poor clinical outcomes. Several analyses of clinical trials have shown mixed results with regards to whether a carbapenem must be used to treat serious infections caused by ESBLs or whether some of the older β-lactam-β-lactamase combinations such as piperacillin/tazobactam are appropriate. Some of the newer combinations such as ceftazidime/avibactam have demonstrated efficacy in patients. ESBL-producing Gram-negative pathogens will continue to be major contributor to antimicrobial resistance worldwide. It is essential that we remain vigilant about identifying them both in patient isolates and through surveillance studies.

Clonal outbreak caused by VIM-4-producing Proteus mirabilis in a Greek tertiary-care hospital

Carbapenem-resistant Enterobacterales have become a major public-health issue worldwide. Here we report an outbreak caused by a clonal multidrug-resistant Proteus mirabilis strain producing VIM-4 metallo-β-lactamase (MBL) and TEM-2 β-lactamase in a Greek tertiary-care hospital. From July 2015 to February 2016, 27 imipenem-resistant P. mirabilis isolates were recovered from 14 patients hospitalised in two intensive care units (ICUs) and the internal medicine department in AHEPA University Hospital, Thessaloniki. The isolates were either susceptible or resistant to meropenem and were resistant to all remaining β-lactams except aztreonam. Phenotypic and molecular analysis revealed that all of the isolates harboured a bla_VIM-4 MBL gene. Resistome analysis of a representative isolate showed the presence of an IncQ1 plasmid harbouring the bla_VIM-4 carbapenemase and bla_TEM-2 β-lactamase genes among resistance genes coding for resistance to β-lactams, aminoglycosides, trimethoprim, sulfonamides and lincosamides. Genotyping by pulsed-field electrophoresis (PFGE) revealed that the isolates were epidemiologically related. After recovery of the index carbapenemase-producing P. mirabilis clinical isolate, infection control measures were intensified in the affected departments. Rectal sampling for carbapenem-resistant bacteria was initiated on a weekly basis among patients admitted to the general ICU. The outbreak was finally interrupted 6 months later in February 2016. This is the first documentation of the bla_VIM-4 MBL gene in P. mirabilis as well as the first hospital outbreak caused by a MBL-producing P. mirabilis strain.

Liposomal-lipopolysaccharide vaccine extracted from Proteus mirabilis induces moderate TLR4 and CD14 production

Proteus mirabilis is a common cause of recurrent urinary tract infections in individuals with functional or structural abnormalities. It also forms bladder and kidney stones. Lipopolysaccharide (LPS) is a potential Proteus virulence factor that plays a key role in pathogenesis, as well as in stimulating innate immune response. Therefore, this study aimed to extract LPS from a highly resistant isolate and incorporate it in a delivery system (liposome) to stimulate an immune response against virulent pathogens. In the work, 50 isolates of P. mirabilis were taken from 200 urine specimens obtained from recurrent-urinary tract infections (UTI) of patients of AL-Sadar Hospital. Specimens were cultured on specific media, and then bacterial isolates were identified via morphological, biochemical and Vitek-2 systems. The results showed that P. mirabilis was expressed in 11 (22%), 30 (60%) and 9 (18%) recurrent UTI, kidney stone and catheter samples, respectively. All isolates were assessed through antibiogram testing, with the results revealing that most isolates were multidrug resistant to more than 3 classes of antibiotics. Herein, P. mirabilis NO 50 revealed particularly high resistance, so it was chosen for LPS extraction. Lethal dose 50 (LD50) observations indicated that a live suspension of P. mirabilis was at 4.5×107 CFU/ml, while LPS was at 270 μg/ml. LPS was used as an immunogenic to stimulate the immune system through injecting Rats intraperitoneally (I.P.) with 1 ml of LD50%. Subsequently, the efficiency of immunogenes in stimulating the immune response was evaluated by determining the Toll-like receptor and CD14 levels. The results indicate that LPS incorporated in the Liposome released moderate levels of Toll-like receptors-4 (TLR4) that enabled the immune system to clear pathogens. The LPS+ complete Freund’s adjuvant (CFA) and LPS vaccinated groups recorded hyper production for TLR4 (52.2 and 40.9 pg/ml, respectively), this was followed by liposome (LIP) and bacterial suspension (11 and 20.5 pg/ml, respectively) in ranking effectiveness. This study reveals a mean of CD14 that was higher in both LPS and LPS+CFA and moderate in LPS+LIP, in comparison with control and liposome groups.

In conclusion, LPS-Liposomes are a promising nanomedicine for modulating the hyper response of LPS. This may lead to tissue inflammation but appeared beneficial in stimulating the immune response at moderate levels so as to eradicate infection without tissue damage.

Analysis of Clinical Isolates of Extended-Spectrum β-Lactamase-Producing Bacteria with Primer and Probe Sets Developed to Detect blaCTX-M, blaTEM, and blaSHV Using a Fully Automated Gene Detection System

In this study, we evaluated extended-spectrum β-lactamase (ESBL)-producing bacteria with the newly developed primer and probe sets to detect bla_CTX-M, bla_TEM, and bla_SHV using BD MAX^TM, a fully automated multiplex polymerase chain reaction assay system. In 36 isolates confirmed by whole-genome sequencing to have bla_CTX-M, bla_TEM, or bla_SHV, the developed primer and probe sets accurately detected each gene without being influenced by the presence of other β-lactamase genes. In nine control strains that do not harbor either bla_CTX-M, bla_TEM, or bla_SHV no cross-reaction was observed. In 191 strains phenotypically determined to be ESBL-producers by conventional antimicrobial susceptibility tests, 189 strains were blaC_TX-M-, bla_TEM-, or bla_SHV-positive as assessed by BD MAX^TM using the developed primer and probe sets, and two strains were negative for these genes. Whole-genome sequencing revealed that these two strains were phenotypically false-positive ESBL-producers. The accuracy of the primer and probe sets seems to be satisfactory, and they may be applicable to detect CTX-M-type ESBL-producing bacteria.

CTX-M-15 is Established in Most Multidrug-Resistant Uropathogenic Enterobacteriaceae and Pseudomonaceae from Hospitals in Nigeria

β-Lactam antibiotics are widely used to treat urinary tract infections in Nigeria. This study aimed to determine the presence and characteristics of extended spectrum β-lactamases in commonly isolated uropathogenic Gram-negative bacteria (GNB) in Nigeria. Fifty non-duplicate GNB isolates consisting of Escherichia coli, 19; Klebsiella pneumoniae, 21; and Pseudomonas aeruginosa, 10 were obtained from three tertiary hospitals in Nigeria. The antibiotic susceptibility testing of all isolates to a panel of antibiotics including minimum inhibitory concentrations (MICs) and extended spectrum β-lactamases was determined. Polymerase chain reactions and sequencing were used to detect β-lactam genes. Polymerase chain reactions and sequencing identified varying extended spectrum β-lactamases (ESBLs) encoding genes for 24 isolates (48.0%). Cefotaximase-Munich (CTX-M) 15 was the dominant gene with 20/24 of the isolates positive at 83.3%; multiple genes (2 to 6 ESBL genes) were found in 20 of the isolates. The isolates encoded other genes such as CTX-M-14, 33.3%; sulfhydryl variable (SHV) variants, 58.3%; oxacillinase (OXA) variants, 70.8%; OXA-10, 29.2%; and Vietnamese extended β-lactamase (VEB) 1, 25.0%. There was no difference between the MIC₅₀ and MIC₉₀ of all the isolates. The high-level multidrug resistance of uropathogens to third generation cephalosporins including other antibiotics used in this study is strongly associated with carriage of ESBLs, predominantly CTX-M-15, as well as CTX-X-M-14, OXA-10, and VEB-1.