Quorum Sensing Mediated Pathogenicity, Virulence Genes and Class 1 Integron in Carbapenem-Resistant Clinical Pseudomonas Aeruginosa Isolates

Carbapenems are the most effective agents for treating carbapenem-resistant clinical P. aeruginosa (CRPsA) infections. During an infection, a quorum-sensing (QS) system and its regulating virulence genes have a great role. The aim of the study was to detect the presence of a las and rhl QS system and related virulence genes and a class 1 (Cls1) integron. A total of 52 CRPsA isolates obtained from Kastamonu, Turkey was analyzed. A conventional culture method, an oprL gene-based molecular assay for P. aeruginosa isolates, and an automated VITEK-2 compact system were applied for the isolation and identification of CRPsA isolates. The oprL gene was detected in all of the isolates tested. At least one of the las or rhl system genes was detected in 98.07% of the isolates, and the percentage of las system genes (98.07%) were higher than that of rhl system genes (90.38%). algD, lasB, toxA and aprA genes were detected in between 46.15% and 88.46% of the isolates, and co-existence of four genes were detected in 40.38% of the isolates. Cls1 integron and slime production using Congo Red Agar (CRA) were present in 51.92% and 67.30%, respectively, of the isolates. There was a significant positive correlation (p <.10) between the las system and the rhl system and a strongly positive correlation (p<.01 or p <.05) between the rhl system-four virulence genes and slime production-and among some virulence genes. In conclusion, the CRPsA isolates tested in the study are highly virulent and QS systems have a significant role in pathogenesis.

The Relationship Between the Use of Hydrogel and Silicone Hydrogel Contact Lenses and Coagulase-Negative Staphylococci Population in the Conjunctiva and Biofilm Forming Staphylococcus epidermidis

Objective: The most important bacteria of the conjunctival microbiota are Staphylococcus epidermidis, diphteroid rods, Corynebacterium spp. and Cutibacterium acnes. Especially biofilm formation of S. epidermidis is very important for contact lens related infections. For this purpose, we aimed to examine the changes in the presence of biofilm-forming S. epidermidis and other coagulase-negative staphylococci in conjunctival swabs taken before and after lens usage in 140 patients (90 hydrogel, 50 silicone hydrogel) who were prepared to wear lenses. Methods: Coagulase-negative staphylococci isolated from the conjunctival microbiota identified standard clinical microbiological methods, after identification of S.epidermidis strains with API Staph; Slime production was determined by Congo red agar, standard tube and molecular methods. Results: S.epidermidis was the most frequently isolated species in conjunctival microbiota before and after lens usage. Before lens usage, slime positive S. epidermidis strains were found as 45-50% but after lens usage it was 59% in hydrogel contact lens users and 70.2% in silicone hydrogel contact lens users. For the investigation of slime production, 82 (50.9%) of 161 S. epidermidis strains were found positive by using Congo red agar, 61 (37.8%) by standard tube method and 91 (56.5%) by molecular methods. Conclusion: The result of our study suggests that there are no significant changes in bacterial ratios before and after lens use, but bacteria such as S. epidermidis can predispose to infections by using slime production and contact lens factor. Also; molecular methods and Congo Red Agar method were found to be more reliable than the Standard Tube method.

Slime Production by Staphylococcus aureus isolated from raw milk samples of various regions of Jaipur city of Rajasthan state, India

The present study was conducted to characterize the slime production activity of Staphylococcus aureus isolated from raw milk samples of various regions of Jaipur city of Rajasthan, India. Total 144 strains of S. aureus were confirmed by 23S rRNA amplification and 1250 bp product size on agarose gel confirmed S. aureus on molecular level. Slime production was determined by Congo red agar (CRA) method. Out of 144 S. aureus strains 134 (93.06%) produced slime and maximum slime production was found in Durgapura (100%) region followed by Mansarovar (95.65%) region and lowest slime production was found in Jhotwara area of Jaipur city of Rajasthan. This study provides an idea that infection of S. aureus may pose a potential risk to human health and these results may support the future actions related to milk safety programs.

Investigation of the presence of slime production, VanA gene and antiseptic resistance genes in Staphylococci isolated from bovine mastitis in Algeria

Staphylococcus strains are frequently as- sociated with clinical and subclinical bovine intra-mammary infection. The virulence factors of staphylococcus have not been widely studied in Algeria. The objective of this study was to determine the frequency of slime production, VanA gene and antiseptic resistance genes in staphylococci strains isolated from bovine mas- titis in Algeria. The study examined 35 Staphy- lococci strains obtained from the inflammatory secretion of mammary glands of cows with mastitis. Slime production was determined by detecting the icaA and icaD genes using the polymerase chain reaction (PCR) method and Congo red agar (CRA) method. The presence of qacAB and qac C antiseptic resistance genes and the VanA resistance gene in these isolates was investigated by PCR. The results of the current study revealed that of the 35 Staphylo- cocci isolates, 42.85% (15/35) and 17.14% (6/35) of the isolates harboured the slime production gene by analysing icaA and icaD genes, respec- tively and 71.42% (25/35) by the CRA method. However, VanA and antiseptic resistance genes (qacAB and qac C) were not detected in any of the isolates. Therefore, the majority of Staphylo- coccus strains were capable of producing slime, and the CRA detection rate was higher than the PCR method for the biofilm-producing capac- ity of Staphylococcus strains. Thus, the presence of the ica genes in Staphylococcus strains con- firms its role as a virulence factor in the patho- genesis of bovine mastitis.

Biofilm Formation Ability and Presence of Adhesion Genes among Coagulase-Negative and Coagulase-Positive Staphylococci Isolates from Raw Cow’s Milk

The capacity for biofilm formation is one of the crucial factors of staphylococcal virulence. The occurrence of biofilm-forming staphylococci in raw milk may result in disturbances in technological processes in dairy factories as well as the contamination of finished food products. Therefore, this study aimed to determine the prevalence and characteristics of staphylococcal biofilm formation in raw milk samples and to explore the genetic background associated with biofilm formation in those isolates. The material subjected to testing included 30 cow’s milk samples acquired from farms in the central part of Poland. A total of 54 staphylococcal strains were isolated from the samples, of which 42 were classified as coagulase-negative (CoNS) staphylococci belonging to the following species: S. haemolyticus, S. simulans, S. warneri, S. chromogenes, S. hominis, S. sciuri, S. capitis, S. xylosus and S. saprophyticus, while 12 were classified as S. aureus. The study examined the isolates’ capacity for biofilm formation and the staphylococcal capacity for slime production and determined the presence of genetic determinants responsible for biofilm formation, i.e., the icaA, icaD, bap and eno and, additionally, among coagulase-negative staphylococci, i.e., the aap, bhp, fbe, embP and atlE. Each tested isolate exhibited the capacity for biofilm formation, of which most of them (79.6%) were capable of forming a strong biofilm, while 5.6% formed a moderate biofilm, and 14.8% a weak biofilm. A capacity for slime production was demonstrated in 51.9% isolates. Most of the tested staphylococcal strains (90.7%) had at least one of the tested genes. Nearly half (47.6%) of the CoNS had the eno gene, while for S. aureus, the eno gene was demonstrated in 58.3% isolates. The frequency of the bap gene occurrence was 23.8% and 25% in CoNS strains and S. aureus, respectively. The fbe gene was demonstrated in only three CoNS isolates. The presence of the icaA was only demonstrated in CoNS strains (24.1%), while the icaD was found in both CoNS strains (21.4%) and S. aureus (100%). Among the CoNS, the presence of the embP (16.7%), aap (28.6%) and atlE (23.8%) was demonstrated as well. The obtained study results indicate that bacteria of the Staphylococcus spp. genus have a strong potential to form a biofilm, which may pose a hazard to consumer health.

Laboratory evaluation of different formulations of Stress Coat® for slime production in goldfish (Carassius auratus) and koi (Cyprinus carpio)

A study was carried out to assess the effect of Stress Coat® on slime production in goldfish (Carassius auratus) and koi (Cyprinus carpio). The study also investigated histological changes that might be associated with slime producing cells, and wound healing in koi. Several formulations of Stress Coat® were investigated and the results showed that polyvinylpyrrolidone (PVP), also known as povidone, an ingredient of Stress Coat®, when used alone, showed significantly higher slime production in goldfish than salt and Stress Coat® without PVP after 25 h. The results also showed that koi treated with compounds containing PVP showed better wound healing than those not exposed to PVP. Histology results showed no difference between compounds tested with regards to density and number of slime producing cells.

Clinical and antimicrobial profile of Coagulase Negative staphylococci in a tertiary care hospital

Background: Coagulase negative staphylococci (CoNS) are gaining importance because of their role as pathogens in certain clinical conditions and their marked resistance to antibiotics. Their species distribution and slime production has important correlation with the antimicrobial susceptibility pattern. Aim of this study was to determine clinically significant CoNS, their species distribution, slime production and antimicrobial susceptibility pattern in a tertiary care hospital.Methods: Identification, speciation and antimicrobial sensitivity testing were performed using standard microbiological techniques. Slime production was also tested by microtiter plate. Antimicrobial susceptibility testing was performed by modified Kirby Bauer method as per the CLSI guidelines.Results: A total 204 (49.88%) CoNS were found to be clinically significant. Percentage of clinical significance was high in urine isolates (88.88%) followed by pus (47.78%) and blood (45.56%). The most common CoNS infection was septicaemia (54.9%) followed by abscesses and wound infections (26.5%) and urinary tract infection (15.8%). S. epidermidis (46.1%) was the commonest species in CoNS infection followed by S. haemolyticus (22.1%), S. lugdunensis (11.8%) and S. saprophyticus (8.3%). Slime production was seen in 56.4% isolates by microtiter plate method. Maximum resistance was seen to penicillin (92.25%), followed by cotrimoxazole (73.03%), norfloxacin (73.03%), tetracycline (71.07%), gentamicin (69.6%) and cefoxitin (63.2%).Conclusions: The role of CoNS as pathogen, particularly nosocomial and opportunistic is increasing. Identification of species, slime production and antimicrobial susceptibility of CoNS is highly desirable to permit a more precise determination of host-pathogen relationship and knowledge of pathogenicity.