Jundishapur Journal of Microbiology
Volume:12 Issue: 12, Dec 2019

Methicillin-resistant Staphylococcus aureus (MRSA) is the most imperative cause of nosocomial infections. Cockroaches are the routine insects accountable for the spread of resistant bacterial strains, exclusively MRSA.

The current survey aimed to appraise the frequency of Panton-Valentine leucocidin (PVL) and Staphylococcal cassette chromosome mec (SCCmec) in MRSA bacteria recovered from hospital cockroaches.

Thirty-six MRSA isolates were recovered from the external washing samples of American and German hospital cockroaches. Bacteria were subjected to the PCR amplification of SCCmec types and the PVL gene.

The SCCmec types III (44.44%), I (27.77%), and II (16.66%) were the most frequent types among MRSA bacteria. The frequency of SCCmec types IVa, IVd, and V was 2.77%, 2.77%, and 5.55%, respectively. The SCCmec types IVb and IVc were not detected in the assessed samples. Twelve out of 36 (33.33%) MRSA isolates harbored the PVL gene. The frequency of the PVL gene was 35.71% and 25%, respectively, among MRSA bacteria recovered from Periplaneta americana and Blattella germanica hospital cockroaches.

The current research is an initial description of SCCmec types and the PVL gene among MRSA bacteria recovered from hospital cockroaches. High frequency of SCCmec types I, II, and III and moderate-to-low frequency of the PVL gene signify the occurrence of health care associated-MRSA.

Leishmania infantum parasites are the main causative agents of visceral leishmaniasis that threaten a wide range of humans and canines in Iran.

Our aim was to survey Leishmania parasite species and simultaneous comparison of canine organs in endemic areas for the diagnosis of visceral leishmaniasis using the ITS-rDNA gene, sequencing, and phylogenetic analysis.

In this study, sampling was done with vacuum tubes containing EDTA from blood and sterile swabs from the snout and conjunctiva of asymptomatic sheepdogs (n = 37) using a non-invasive method in north Khorasan, northeastern Iran, from 28 July to 4 August 2018. The DNA of collected samples was extracted, amplified, and sequenced by targeting the ITS-rDNA gene. To demonstrate the taxonomic status of Leishmania spp., sequences were subjected to phylogenetic analysis based on the maximum likelihood method.

We obtained 37 samples from asymptomatic dogs of which, 10 dogs were definitely diagnosed with L. infantum and one dog infected with L. tropica. The blood (n = 8) and right conjunctiva (n = 6) samples were the most infected samples. The highest number of infections in dogs was in the age group of 5 - 10 years indicating that this group is more sensitive to visceral leishmaniasis in this region.

The current findings indicate that non-invasive sampling and molecular methods are reliable and suitable in the detection of visceral leishmaniasis. This is the first report of the visceral involvement of a shepherd dog with L. tropica in northeastern Iran. The remarkable occurrence of visceral leishmaniasis (29.7%) in asymptomatic sheepdogs reflects a health alert to conduct the surveillance and monitoring of susceptible individuals/reservoirs in the region.

Pseudomonas aeruginosa is recognized as a serious opportunistic pathogen that causes infections in hospitalized patients and shows a high level of antibiotic resistance.

The current study aimed at investigating the frequency of class 1, 2 integrons in P. aeruginosa strains isolated from hospitalized patients in Markazi Province, Iran.

Totally, 100 clinical isolates of P. aeruginosa were collected and identified using standard biochemical tests P. aeruginosa. Antibiotic sensitivity test was performed using disk-diffusion (Bauer-Kirby) method. DNA was extracted, then polymerase chain reaction (PCR) was performed for the detection of class 1 and 2 integrons.

Trimethoprim/sulfamethoxazole (76%) and cefotaxime (45%) were the most effective antimicrobial agents in this study. Also, PCR results showed that 95% of P. aeruginosa strains carried int1, but none of the isolates harbored the int2 genes. A significant correlation was observed between class 1 integrons and resistance to trimethoprim/sulfamethoxazole and cefotaxime (P < 0.005).

The current study recognized a high prevalence of antibiotic resistance also a high presence of class 1 integron. Since integron-carrying elements are responsible for the transmission of antibiotic resistance genes introduced into the hospital is of concern; thus applying comprehensive strategies for prevention and control of infections is necessary.

Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant microorganism and the predominant nosocomial pathogen all over the world. The potential benefits of probiotic lactobacilli against pathogenic bacteria have been shown in many studies.

This study aimed to investigate the effect of cell-free culture supernatant (CFS) of probiotic Lactobacillus spp, including Lactobacillus reuteri, L. plantarum, and L. fermentum, on virulence factor gene expression of MRSA.

Lactobacilli were cultured in MRS and the cells were harvested by centrifuging at 10,000 × g for 10 min at 4°C. The pellet was discarded and 1/2 and 1/4 CFS concentrations from Lactobacillus spp were added to the medium (MHB) containing 107 CFU/mL of the MRSA strain. A quantitative polymerase chain reaction (qPCR) was performed to measure the expression of virulence factors at the transcriptional level.

The results showed that lactobacilli CFS had no obvious inhibitory effects on the growth of S. aureus. The qPCR assay showed that the expression levels of sea, sae, agr A, tst, spa, and spi genes reduced at different levels, depending on the concentration of CFS and the species of lactobacilli so that the maximum significant down-regulation rate was observed in the sea and tst genes (up to 23.5 folds in the presence of 1/2 concentration of L. reuteri CFS after 12 h incubation).

Cell-free culture supernatants of probiotic bacteria can down-regulate the virulence genes. Consequently, toxins and enzymes are less produced by S. aureus as a food-borne pathogen. Therefore, the presence of CFS in the food probably reduces diarrhea and vomiting caused by S. aureus.

Interconnection among bacteria and other infectious agents can transfer the genetic elements such as antibiotic resistance genes. Biofilm or such an established structure could worsen when pathogenic bacteria are in the community. The recognition of bacterial behaviors and characteristics in biofilm community or planktonic forms such as antibiotic resistance spreading is an important and essential matter.

The current study aimed at investigating the correlation between biofilm-producing ability and antibiotic resistance patterns in some pathogenic strains of Aeromonas hydrophila.

In this study, 19 strains of A. hydrophila isolated from infected carps with septicemia were identified by culture and biochemical tests. The isolated strains suspected as A. hydrophila were confirmed by duplex-PCR at both genus and species levels. The biofilm-producing ability of the confirmed isolates was evaluated by the microtiter plate crystal violet method. Antibiogram was designed for isolates by the Kirby-Bauer disc diffusion method.

All the strains were positive for biofilm production ability. Moderate and strong biofilm-producing abilities were detected in 79% and 21% of the isolates, respectively. The majority of the strains (90%) were resistant to clindamycin and vancomycin and all the strains (100%) were susceptible to ciprofloxacin and trimethoprim-sulfamethoxazole.

Strong biofilm-producing strains were resistant to 75% of the studied antibiotics but moderate biofilm-producing strains had different susceptibility rates to the studied antibiotics. An important correlation was detected between the biofilm-producing level (moderate and strong) and antibiotic resistance against tetracycline, oxytetracycline, and amoxicillin. Because of the different ways of resistance acquisition in biofilm-producing bacteria, more studies are needed for understanding the main route.

Spondylodiscitis is an infectious inflammatory disease with the involvement of an intervertebral disk and adjacent vertebral bodies. Hematogenic spreading of microorganisms from an infectious site is the most common pathophysiologic cause of vertebral osteomyelitis. In this report, a case of Escherichia coli spondylodiscitis was described and a review of literature was also performed on cases with E. coli spondylodiscitis.

A 68-year-old woman referred to our hospital with a 2-month history of intermittent fever, weight loss, and low back pain. On physical examination, we found obvious bulging with the dimensions of 4 × 20 cm on about L1 - L4 vertebral area. Lumbosacral MRI revealed the evidence of L2 - L3 spondylodiscitis. She had positive blood and urine cultures with ciprofloxacin-sensitive E. coli and successfully treated without surgery after 8 weeks. Nine articles (including 9 patients) regarding E. coli spondylodiscitis or vertebral osteomyelitis have been published from the 1st of January 1985 to the 10th of August 2019. In addition to these cases, here we report 10th case of E. coli vertebral osteomyelitis. Four patients were female and 6 were male. The mean age was 52 years with a range of 12 - 69. Seven cases had a history of fever, and overall, fever and pain at the site of vertebral involvement were the most common symptoms.

In our reported patient, returning to the patient’s medical history and finding a previous urinary tract infection and E. coli bacteremia was crucial in helping to diagnose and treat the patient. In our review, 7 patients had positive blood cultures, a finding that emphasizes the diagnostic value of this test. Escherichia coli spondylodiscitis is a relatively rare disease that has usually a source of urinary tract infection and its clinical signs and symptoms are not distinguishable from vertebral osteomyelitis due to other agents and finally, blood culture can be helpful as a diagnostic method.